The Bitz, as I understand, comes standard with the cock feather out nock receiver. It is extra $ if you want the cock feather down "Model TM" nock receiver.

As the others have said, if you don't have glue on nocks, then you don't need the cock feather down receiver. When you get the Bitz, you will understand the nock receiver mystery as they explain it in the instructions. Have fun!

The Mouse