diff --git a/pmap.go b/pmap.go
index 3785b9e..7510237 100644
--- a/pmap.go
+++ b/pmap.go
@@ -11,8 +11,8 @@ const (
 	nodeMask   = 0b1111
 )
 
-type Key = interface{}
-type Value = interface{}
+type Key = int
+type Value = int
 
 type Map interface {
 	Get(Key) (Value, bool)
diff --git a/pmap_test.go b/pmap_test.go
index 735ca4d..ca96b59 100644
--- a/pmap_test.go
+++ b/pmap_test.go
@@ -8,7 +8,7 @@ import (
 func hash(k Key) uint32 {
 	//u := uint(k.(int))*6364136223846793005 + 1
 	//return uint32(u >> 32)
-	u := uint(k.(int))
+	u := uint(k) //u := uint(k.(int))
 	return uint32(u + u>>32)
 }