diff --git a/TransactionProcessor.BusinessLogic/Services/TransactionDomainService.cs b/TransactionProcessor.BusinessLogic/Services/TransactionDomainService.cs
index f776ef24..cf971820 100644
--- a/TransactionProcessor.BusinessLogic/Services/TransactionDomainService.cs
+++ b/TransactionProcessor.BusinessLogic/Services/TransactionDomainService.cs
@@ -2,6 +2,7 @@
 {
     using System;
     using System.Collections.Generic;
+    using System.Diagnostics.CodeAnalysis;
     using System.Diagnostics.Eventing.Reader;
     using System.Linq;
     using System.Threading;
@@ -267,6 +268,7 @@ await this.TransactionAggregateManager.RecordAdditionalResponseData(estateId,
         /// <param name="fieldName">Name of the field.</param>
         /// <param name="additionalTransactionMetadata">The additional transaction metadata.</param>
         /// <returns></returns>
+        [ExcludeFromCodeCoverage]
         private T ExtractFieldFromMetadata<T>(String fieldName,
                                                    Dictionary<String, String> additionalTransactionMetadata)
         {
@@ -304,6 +306,7 @@ await this.EstateClient.AddDeviceToMerchant(this.TokenResponse.AccessToken,
         /// Generates the transaction reference.
         /// </summary>
         /// <returns></returns>
+        [ExcludeFromCodeCoverage]
         private String GenerateTransactionReference()
         {
             Int64 i = 1;
diff --git a/TransactionProcessor.Testing/TestData.cs b/TransactionProcessor.Testing/TestData.cs
index 8bddd476..4e2fe0c4 100644
--- a/TransactionProcessor.Testing/TestData.cs
+++ b/TransactionProcessor.Testing/TestData.cs
@@ -29,6 +29,10 @@ public class TestData
 
         public static Guid EstateId = Guid.Parse("A522FA27-F9D0-470A-A88D-325DED3B62EE");
 
+        public static Guid ContractId = Guid.Parse("97A9ED00-E522-428C-B3C3-5931092DBDCE");
+
+        public static Guid ProductId = Guid.Parse("ABA0E536-4E43-4E26-8362-7FB549DDA534");
+
         public static String EstateName = "Test Estate 1";
 
         public static String FailedSafaricomTopup =
diff --git a/TransactionProcessor.Transaction.DomainEvents/ProductDetailsAddedToTransactionEvent.cs b/TransactionProcessor.Transaction.DomainEvents/ProductDetailsAddedToTransactionEvent.cs
new file mode 100644
index 00000000..3c6614bc
--- /dev/null
+++ b/TransactionProcessor.Transaction.DomainEvents/ProductDetailsAddedToTransactionEvent.cs
@@ -0,0 +1,98 @@
+namespace TransactionProcessor.Transaction.DomainEvents
+{
+    using System;
+    using Newtonsoft.Json;
+    using Shared.DomainDrivenDesign.EventSourcing;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <seealso cref="Shared.DomainDrivenDesign.EventSourcing.DomainEvent" />
+    [JsonObject]
+    public class ProductDetailsAddedToTransactionEvent : DomainEvent
+    {
+        #region Constructors
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ProductDetailsAddedToTransactionEvent" /> class.
+        /// </summary>
+        /// <param name="aggregateId">The aggregate identifier.</param>
+        /// <param name="eventId">The event identifier.</param>
+        /// <param name="estateId">The estate identifier.</param>
+        /// <param name="contractId">The contract identifier.</param>
+        /// <param name="productId">The product identifier.</param>
+        private ProductDetailsAddedToTransactionEvent(Guid aggregateId,
+                                                      Guid eventId,
+                                                      Guid estateId,
+                                                      Guid contractId,
+                                                      Guid productId) : base(aggregateId, eventId)
+        {
+            this.TransactionId = aggregateId;
+            this.EstateId = estateId;
+            this.ContractId = contractId;
+            this.ProductId = productId;
+        }
+
+        #endregion
+
+        #region Properties
+
+        /// <summary>
+        /// Gets the contract identifier.
+        /// </summary>
+        /// <value>
+        /// The contract identifier.
+        /// </value>
+        [JsonProperty]
+        public Guid ContractId { get; private set; }
+
+        /// <summary>
+        /// Gets the estate identifier.
+        /// </summary>
+        /// <value>
+        /// The estate identifier.
+        /// </value>
+        [JsonProperty]
+        public Guid EstateId { get; private set; }
+
+        /// <summary>
+        /// Gets the product identifier.
+        /// </summary>
+        /// <value>
+        /// The product identifier.
+        /// </value>
+        [JsonProperty]
+        public Guid ProductId { get; private set; }
+
+        /// <summary>
+        /// Gets the transaction identifier.
+        /// </summary>
+        /// <value>
+        /// The transaction identifier.
+        /// </value>
+        [JsonProperty]
+        public Guid TransactionId { get; private set; }
+
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Creates the specified aggregate identifier.
+        /// </summary>
+        /// <param name="aggregateId">The aggregate identifier.</param>
+        /// <param name="estateId">The estate identifier.</param>
+        /// <param name="contractId">The contract identifier.</param>
+        /// <param name="productId">The product identifier.</param>
+        /// <returns></returns>
+        public static ProductDetailsAddedToTransactionEvent Create(Guid aggregateId,
+                                                                   Guid estateId,
+                                                                   Guid contractId,
+                                                                   Guid productId)
+        {
+            return new ProductDetailsAddedToTransactionEvent(aggregateId, Guid.NewGuid(), estateId, contractId, productId);
+        }
+
+        #endregion
+    }
+}
\ No newline at end of file
diff --git a/TransactionProcessor.TransactionAggregate.Tests/DomainEventTests.cs b/TransactionProcessor.TransactionAggregate.Tests/DomainEventTests.cs
index cb2dcbbc..ab646489 100644
--- a/TransactionProcessor.TransactionAggregate.Tests/DomainEventTests.cs
+++ b/TransactionProcessor.TransactionAggregate.Tests/DomainEventTests.cs
@@ -230,5 +230,21 @@ public void CustomerEmailReceiptRequestedEvent_CanBeCreated_IsCreated()
             customerEmailReceiptRequestedEvent.MerchantId.ShouldBe(TestData.MerchantId);
             customerEmailReceiptRequestedEvent.CustomerEmailAddress.ShouldBe(TestData.CustomerEmailAddress);
         }
+
+        [Fact]
+        public void ProductDetailsAddedToTransactionEvent_CanBeCreated_IsCreated()
+        {
+            ProductDetailsAddedToTransactionEvent productDetailsAddedToTransactionEvent = ProductDetailsAddedToTransactionEvent.Create(TestData.TransactionId, TestData.EstateId,TestData.ContractId, TestData.ProductId);
+
+            productDetailsAddedToTransactionEvent.ShouldNotBeNull();
+            productDetailsAddedToTransactionEvent.AggregateId.ShouldBe(TestData.TransactionId);
+            productDetailsAddedToTransactionEvent.EventCreatedDateTime.ShouldNotBe(DateTime.MinValue);
+            productDetailsAddedToTransactionEvent.EventId.ShouldNotBe(Guid.Empty);
+            productDetailsAddedToTransactionEvent.TransactionId.ShouldBe(TestData.TransactionId);
+            productDetailsAddedToTransactionEvent.EstateId.ShouldBe(TestData.EstateId);
+            productDetailsAddedToTransactionEvent.ProductId.ShouldBe(TestData.ProductId);
+            productDetailsAddedToTransactionEvent.ContractId.ShouldBe(TestData.ContractId);
+
+        }
     }
 }
diff --git a/TransactionProcessor.TransactionAggregate.Tests/TransactionAggregateTests.cs b/TransactionProcessor.TransactionAggregate.Tests/TransactionAggregateTests.cs
index 82678be7..aee7b755 100644
--- a/TransactionProcessor.TransactionAggregate.Tests/TransactionAggregateTests.cs
+++ b/TransactionProcessor.TransactionAggregate.Tests/TransactionAggregateTests.cs
@@ -18,7 +18,6 @@ public void TransactionAggregate_CanBeCreated_IsCreated()
         }
 
         [Theory]
-        [InlineData(TransactionType.Logon)]
         [InlineData(TransactionType.Sale)]
         public void TransactionAggregate_StartTransaction_TransactionIsStarted(TransactionType transactionType)
         {
@@ -38,6 +37,25 @@ public void TransactionAggregate_StartTransaction_TransactionIsStarted(Transacti
             transactionAggregate.TransactionAmount.ShouldBe(TestData.TransactionAmount);
         }
 
+        [Theory]
+        [InlineData(TransactionType.Logon)]
+        public void TransactionAggregate_StartTransaction_NullAmount_TransactionIsStarted(TransactionType transactionType)
+        {
+            TransactionAggregate transactionAggregate = TransactionAggregate.Create(TestData.TransactionId);
+            transactionAggregate.StartTransaction(TestData.TransactionDateTime, TestData.TransactionNumber, transactionType,
+                                                  TestData.TransactionReference, TestData.EstateId, TestData.MerchantId, TestData.DeviceIdentifier, null);
+
+            transactionAggregate.IsStarted.ShouldBeTrue();
+            transactionAggregate.TransactionDateTime.ShouldBe(TestData.TransactionDateTime);
+            transactionAggregate.TransactionNumber.ShouldBe(TestData.TransactionNumber);
+            transactionAggregate.TransactionType.ShouldBe(transactionType);
+            transactionAggregate.EstateId.ShouldBe(TestData.EstateId);
+            transactionAggregate.MerchantId.ShouldBe(TestData.MerchantId);
+            transactionAggregate.DeviceIdentifier.ShouldBe(TestData.DeviceIdentifier);
+            transactionAggregate.TransactionReference.ShouldBe(TestData.TransactionReference);
+            transactionAggregate.TransactionAmount.ShouldBeNull();
+        }
+
         [Theory]
         [InlineData(TransactionType.Logon)]
         [InlineData(TransactionType.Sale)]
@@ -144,6 +162,65 @@ public void TransactionAggregate_StartTransaction_InvalidData_ErrorThrown(Boolea
                                                     });
         }
 
+        [Theory]
+        [InlineData(TransactionType.Sale)]
+        public void TransactionAggregate_AddProductDetails_ProductDetailsAdded(TransactionType transactionType)
+        {
+            TransactionAggregate transactionAggregate = TransactionAggregate.Create(TestData.TransactionId);
+            transactionAggregate.StartTransaction(TestData.TransactionDateTime, TestData.TransactionNumber, transactionType, TestData.TransactionReference, TestData.EstateId, TestData.MerchantId, TestData.DeviceIdentifier,
+                                                  TestData.TransactionAmount);
+
+            transactionAggregate.AddProductDetails(TestData.ContractId,TestData.ProductId);
+
+            transactionAggregate.IsProductDetailsAdded.ShouldBeTrue();
+            transactionAggregate.ContractId.ShouldBe(TestData.ContractId);
+            transactionAggregate.ProductId.ShouldBe(TestData.ProductId);
+        }
+
+        [Theory]
+        [InlineData(TransactionType.Sale)]
+        public void TransactionAggregate_AddProductDetails_InvalidContractId_ErrorThrown(TransactionType transactionType)
+        {
+            TransactionAggregate transactionAggregate = TransactionAggregate.Create(TestData.TransactionId);
+            transactionAggregate.StartTransaction(TestData.TransactionDateTime, TestData.TransactionNumber, transactionType, TestData.TransactionReference, TestData.EstateId, TestData.MerchantId, TestData.DeviceIdentifier,
+                                                  TestData.TransactionAmount);
+
+            Should.Throw<ArgumentException>(() =>
+                                                {
+                                                    transactionAggregate.AddProductDetails(Guid.Empty, TestData.ProductId);
+                                                });
+        }
+
+        [Theory]
+        [InlineData(TransactionType.Sale)]
+        public void TransactionAggregate_AddProductDetails_InvalidProductId_ErrorThrown(TransactionType transactionType)
+        {
+            TransactionAggregate transactionAggregate = TransactionAggregate.Create(TestData.TransactionId);
+            transactionAggregate.StartTransaction(TestData.TransactionDateTime, TestData.TransactionNumber, transactionType, TestData.TransactionReference, TestData.EstateId, TestData.MerchantId, TestData.DeviceIdentifier,
+                                                  TestData.TransactionAmount);
+
+            Should.Throw<ArgumentException>(() =>
+                                                {
+                                                    transactionAggregate.AddProductDetails(TestData.ContractId, Guid.Empty);
+                                                });
+        }
+
+        [Theory]
+        [InlineData(TransactionType.Sale)]
+        public void TransactionAggregate_AddProductDetails_ProductDetailsAlreadyAdded_ErrorThrown(TransactionType transactionType)
+        {
+            TransactionAggregate transactionAggregate = TransactionAggregate.Create(TestData.TransactionId);
+            transactionAggregate.StartTransaction(TestData.TransactionDateTime, TestData.TransactionNumber, transactionType, TestData.TransactionReference, TestData.EstateId, TestData.MerchantId, TestData.DeviceIdentifier,
+                                                  TestData.TransactionAmount);
+
+            transactionAggregate.AddProductDetails(TestData.ContractId, TestData.ProductId);
+
+            Should.Throw<InvalidOperationException>(() =>
+                                                {
+                                                    transactionAggregate.AddProductDetails(TestData.ContractId, TestData.ProductId);
+                                                });
+        }
+
         [Theory]
         [InlineData(TransactionType.Logon)]
         public void TransactionAggregate_AuthoriseTransactionLocally_TransactionIsAuthorised(TransactionType transactionType)
diff --git a/TransactionProcessor.TransactionAgrgegate/TransactionAggregate.cs b/TransactionProcessor.TransactionAgrgegate/TransactionAggregate.cs
index 9362baf5..19de8f09 100644
--- a/TransactionProcessor.TransactionAgrgegate/TransactionAggregate.cs
+++ b/TransactionProcessor.TransactionAgrgegate/TransactionAggregate.cs
@@ -88,6 +88,21 @@ private TransactionAggregate(Guid aggregateId)
         /// </value>
         public Guid EstateId { get; private set; }
 
+        /// <summary>
+        /// Gets the contract identifier.
+        /// </summary>
+        /// <value>
+        /// The contract identifier.
+        /// </value>
+        public Guid ContractId { get; private set; }
+        /// <summary>
+        /// Gets the product identifier.
+        /// </summary>
+        /// <value>
+        /// The product identifier.
+        /// </value>
+        public Guid ProductId { get; private set; }
+
         /// <summary>
         /// Gets a value indicating whether this instance is authorised.
         /// </summary>
@@ -471,6 +486,27 @@ public void StartTransaction(DateTime transactionDateTime,
             this.ApplyAndPend(transactionHasStartedEvent);
         }
 
+        /// <summary>
+        /// Adds the product details.
+        /// </summary>
+        /// <param name="contractId">The contract identifier.</param>
+        /// <param name="productId">The product identifier.</param>
+        public void AddProductDetails(Guid contractId,
+                                      Guid productId)
+        {
+            Guard.ThrowIfInvalidGuid(contractId, typeof(ArgumentException), $"Contract Id must not be [{Guid.Empty}]");
+            Guard.ThrowIfInvalidGuid(productId, typeof(ArgumentException), $"Product Id must not be [{Guid.Empty}]");
+
+            this.CheckProductDetailsNotAlreadyAdded();
+
+            ProductDetailsAddedToTransactionEvent productDetailsAddedToTransactionEvent = ProductDetailsAddedToTransactionEvent.Create(this.AggregateId,
+                                                                                                                                       this.EstateId,
+                                                                                                                                       contractId,
+                                                                                                                                       productId);
+
+            this.ApplyAndPend(productDetailsAddedToTransactionEvent);
+        }
+
         /// <summary>
         /// Gets the metadata.
         /// </summary>
@@ -493,6 +529,14 @@ protected override void PlayEvent(DomainEvent domainEvent)
             this.PlayEvent((dynamic)domainEvent);
         }
 
+        private void CheckProductDetailsNotAlreadyAdded()
+        {
+            if (this.IsProductDetailsAdded)
+            {
+                throw new InvalidOperationException("Product details already added");
+            }
+        }
+
         /// <summary>
         /// Checks the additional request data not already recorded.
         /// </summary>
@@ -737,6 +781,21 @@ private void PlayEvent(TransactionDeclinedByOperatorEvent domainEvent)
             this.ResponseMessage = domainEvent.ResponseMessage;
         }
 
+        private void PlayEvent(ProductDetailsAddedToTransactionEvent domainEvent)
+        {
+            this.IsProductDetailsAdded = true;
+            this.ContractId = domainEvent.ContractId;
+            this.ProductId = domainEvent.ProductId;
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether this instance is product details added.
+        /// </summary>
+        /// <value>
+        ///   <c>true</c> if this instance is product details added; otherwise, <c>false</c>.
+        /// </value>
+        public Boolean IsProductDetailsAdded { get; private set; }
+
         #endregion
     }
 }
\ No newline at end of file