diff --git a/app/models/comable/cart_item.rb b/app/models/comable/cart_item.rb
index 1d69ebdd..ce7e9ee2 100644
--- a/app/models/comable/cart_item.rb
+++ b/app/models/comable/cart_item.rb
@@ -6,7 +6,6 @@ class CartItem < ActiveRecord::Base
     validates Comable::Customer.foreign_key, uniqueness: { scope: [Comable::Customer.foreign_key, Comable::Stock.foreign_key] }
 
     def stock
-      return comable_stock unless respond_to?(:comable_values)
       return comable_stock unless comable_values[:flag]
       stock = comable_stock
       return if stock.nil?
diff --git a/lib/acts_as_comable_customer/base.rb b/lib/acts_as_comable_customer/base.rb
index 055ca4a7..94c0e7b3 100644
--- a/lib/acts_as_comable_customer/base.rb
+++ b/lib/acts_as_comable_customer/base.rb
@@ -57,9 +57,7 @@ def reset_cart
 
         def cart_items
           return super unless self.logged_in?
-          comable_flag = false
-          comable_flag = comable_values[:flag] if respond_to?(:comable_values)
-          Comable::CartItem.comable(comable_flag).where(Comable::Customer.foreign_key => id)
+          Comable::CartItem.comable(comable_values[:flag]).where(Comable::Customer.foreign_key => id)
         end
 
         def cart
diff --git a/lib/acts_as_comable_product/base.rb b/lib/acts_as_comable_product/base.rb
index 418576dc..2c6c9000 100644
--- a/lib/acts_as_comable_product/base.rb
+++ b/lib/acts_as_comable_product/base.rb
@@ -17,7 +17,6 @@ def acts_as_comable_product
 
       module InstanceMethods
         def stocks
-          return comable_stocks unless respond_to?(:comable_values)
           return comable_stocks unless comable_values[:flag]
           stocks = comable_stocks
           return if stocks.nil?
diff --git a/lib/acts_as_comable_stock/base.rb b/lib/acts_as_comable_stock/base.rb
index a5a04dfe..67e26fa0 100644
--- a/lib/acts_as_comable_stock/base.rb
+++ b/lib/acts_as_comable_stock/base.rb
@@ -21,7 +21,6 @@ def acts_as_comable_stock
 
       module InstanceMethods
         def product
-          return comable_product unless respond_to?(:comable_values)
           return comable_product unless comable_values[:flag]
           product = comable_product
           return if product.nil?
diff --git a/lib/comable/columns_mapper.rb b/lib/comable/columns_mapper.rb
index a2a8ccab..fb45e8b3 100644
--- a/lib/comable/columns_mapper.rb
+++ b/lib/comable/columns_mapper.rb
@@ -194,7 +194,6 @@ def warning_checker
       #
       module RelationMethod
         def relation(*args, &block)
-          return super unless self.respond_to?(:comable)
           return super unless current_scope
           return super unless current_scope.comable_values
           return super unless current_scope.comable_values[:flag]
@@ -219,7 +218,6 @@ module Relation
         #   #=> true (= products.title)
         #
         def to_a
-          return super unless @klass.include?(InstanceMethods)
           return super unless comable_values[:flag]
           super.each { |record| record.comable!(comable_values[:type]) }
         end
diff --git a/lib/comable/customer_session.rb b/lib/comable/customer_session.rb
index da6d09db..2ad3cfac 100644
--- a/lib/comable/customer_session.rb
+++ b/lib/comable/customer_session.rb
@@ -27,9 +27,7 @@ def add_stock_to_cart(stock)
         found_cart_item = found_cart_items.first
         found_cart_item.quantity = found_cart_item.quantity.next
       else
-        comable_flag = false
-        comable_flag = comable_values[:flag] if respond_to?(:comable_values)
-        @cart_items << Comable::CartItem.comable(comable_flag).new(Comable::Stock.foreign_key => stock.id)
+        @cart_items << Comable::CartItem.comable(comable_values[:flag]).new(Comable::Stock.foreign_key => stock.id)
       end
       save_cart_to_session
     end