diff --git a/docs/csharp/whats-new/tutorials/snippets/record-types/InterimSteps.cs b/docs/csharp/whats-new/tutorials/snippets/record-types/InterimSteps.cs
index c268a3ec43c39..05939c8f40ae8 100644
--- a/docs/csharp/whats-new/tutorials/snippets/record-types/InterimSteps.cs
+++ b/docs/csharp/whats-new/tutorials/snippets/record-types/InterimSteps.cs
@@ -19,7 +19,7 @@ public record DailyTemperature(double HighTemp, double LowTemp)
     // <DegreeDaysRecords>
     public abstract record DegreeDays(double BaseTemperature, IEnumerable<DailyTemperature> TempRecords);
 
-    public record HeatingDegreeDays(double BaseTemperature, IEnumerable<DailyTemperature> TempRecords)
+    public sealed record HeatingDegreeDays(double BaseTemperature, IEnumerable<DailyTemperature> TempRecords)
         : DegreeDays(BaseTemperature, TempRecords)
     {
         public double DegreeDays => TempRecords.Where(s => s.Mean < BaseTemperature).Sum(s => BaseTemperature - s.Mean);