I rebuilt an old Strat copy guitar that needed a new neck. The existing neck pocket was undersized so the new neck wouldn't fit. I bought this after reviewing other reviews. The opening is a bit big but all you need to do is use blue tape on the inside faces to reduce the opening size for routing based on the type of finish your neck has. After measuring I determined the correct spacing. The routing came out perfect. The jig template is well made and accurate. Just use some double sided tape to hold in place. Make sure you use blue tape on the guitar finish so the double sided tape won't pull off the finish. I would buy again.