diff --git a/src/EntityComponentReader.cs b/src/EntityComponentReader.cs
index ef19723..2531109 100644
--- a/src/EntityComponentReader.cs
+++ b/src/EntityComponentReader.cs
@@ -4,6 +4,7 @@ public abstract class EntityComponentReader
 {
 	internal EntityStorage EntityStorage;
 	internal ComponentDepot ComponentDepot;
+	protected FilterBuilder FilterBuilder => new FilterBuilder(ComponentDepot);
 
 	internal void RegisterEntityStorage(EntityStorage entityStorage)
 	{
diff --git a/src/System.cs b/src/System.cs
index 12e8dfb..cc00c8e 100644
--- a/src/System.cs
+++ b/src/System.cs
@@ -3,7 +3,6 @@
 public abstract class System : EntityComponentReader
 {
 	internal MessageDepot MessageDepot;
-	public FilterBuilder FilterBuilder => new FilterBuilder(ComponentDepot);
 
 	internal void RegisterMessageDepot(MessageDepot messageDepot)
 	{