diff --git a/Implab/ObjectPoolWrapper.cs b/Implab/ObjectPoolWrapper.cs
--- a/Implab/ObjectPoolWrapper.cs
+++ b/Implab/ObjectPoolWrapper.cs
@@ -1,7 +1,7 @@
 using System;
 
 namespace Implab {
-    public struct ObjectPoolWrapper<T> : IDisposable {
+    public class ObjectPoolWrapper<T> : IDisposable {
         readonly T m_value;
         readonly ObjectPool<T> m_pool;