diff --git a/ext/v8/object.cc b/ext/v8/object.cc
index a890462..09af5dc 100644
--- a/ext/v8/object.cc
+++ b/ext/v8/object.cc
@@ -17,6 +17,11 @@ void Object::Init() {
     defineEnumConst("ReadOnly", v8::ReadOnly).
     defineEnumConst("DontEnum", v8::DontEnum).
     defineEnumConst("DontDelete", v8::DontDelete);
+  ClassBuilder("AccessControl").
+    defineEnumConst("DEFAULT", v8::DEFAULT).
+    defineEnumConst("ALL_CAN_READ", v8::ALL_CAN_READ).
+    defineEnumConst("ALL_CAN_WRITE", v8::ALL_CAN_WRITE).
+    defineEnumConst("PROHIBITS_OVERWRITING", v8::PROHIBITS_OVERWRITING);
 }
 
 VALUE Object::New(VALUE self) {
diff --git a/ext/v8/rr.h b/ext/v8/rr.h
index e6238a4..6263c9a 100644
--- a/ext/v8/rr.h
+++ b/ext/v8/rr.h
@@ -41,7 +41,7 @@ public:
     this->value = value;
   }
   inline operator T() {
-    return NUM2INT(value);
+    return NIL_P(value) ? 0 : NUM2INT(value);
   }
 private:
   VALUE value;
@@ -148,6 +148,7 @@ private:
 };
 
 class PropertyAttribute: public Enum<v8::PropertyAttribute> {};
+class AccessControl: public Enum<v8::AccessControl> {};
 
 class Object : public Ref<v8::Object> {
 public: