diff --git a/lib/index.js b/lib/index.js
index 15e9274..d39176b 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -27,21 +27,21 @@ var cache = {
     if (!callback) return;
     if (!this.dataExpire[key]) return callback(this.data[key]);
 
-    if (this.dataExpire[key]*1000+ this.dataTime[key] < new Date().getTime()/1000) {
+    if (this.dataExpire[key]*1000+ this.dataTime[key] < new Date().getTime()) {
       this.data[key] = null;
-      callback(null);
+      callback(null, null);
     } else {
-      callback(this.data[key]);
+      callback(null, this.data[key]);
     }
   },
   set: function(key, val, callback){
     this.data[key] = val;
     this.dataTime[key] = new Date().getTime();
-    if (callback) callback(val);
+    if (callback) callback(null, val);
   },
   expire: function(key, val, callback){
     this.dataExpire[key] = val;
-    if (callback) callback(val);
+    if (callback) callback(null, val);
   }
 };