diff --git a/src/EcsSubject.cs b/src/EcsSubject.cs
index 9e096ed..beb2df8 100644
--- a/src/EcsSubject.cs
+++ b/src/EcsSubject.cs
@@ -127,9 +127,9 @@ namespace DCFApixels.DragonECS
     #region BuilderBase
     public abstract class EcsSubjectBuilderBase
     {
-        public abstract TPool Include<TComponent, TPool>() where TComponent : struct where TPool : IEcsPoolImplementation<TComponent>, new();
-        public abstract TPool Exclude<TComponent, TPool>() where TComponent : struct where TPool : IEcsPoolImplementation<TComponent>, new();
-        public abstract TPool Optional<TComponent, TPool>() where TComponent : struct where TPool : IEcsPoolImplementation<TComponent>, new();
+        public abstract TPool Include<TComponent, TPool>() where TPool : IEcsPoolImplementation<TComponent>, new();
+        public abstract TPool Exclude<TComponent, TPool>() where TPool : IEcsPoolImplementation<TComponent>, new();
+        public abstract TPool Optional<TComponent, TPool>() where TPool : IEcsPoolImplementation<TComponent>, new();
     }
     #endregion
 
diff --git a/src/EcsWorld.cs b/src/EcsWorld.cs
index 690a5d9..011e480 100644
--- a/src/EcsWorld.cs
+++ b/src/EcsWorld.cs
@@ -121,7 +121,7 @@ namespace DCFApixels.DragonECS
         #endregion
 
         #region GetPool
-        public TPool GetPool<TComponent, TPool>() where TComponent : struct where TPool : IEcsPoolImplementation<TComponent>, new()
+        public TPool GetPool<TComponent, TPool>() where TPool : IEcsPoolImplementation<TComponent>, new()
         {
             int uniqueID = WorldMetaStorage.GetComponentId<TComponent>(_worldTypeID);