Carbon Tech's own tunable nock for the CT Cheetah, CT Whitetail, CT Rhino, CT Cougar, and CT Panther.  Inserts into the CT Cheetah, CT Whitetail, CT Rhino, CT Cougar, and CT Panther.  The tunable nock incorporates an index and alignment feature and nock recess. 
One size fits all! 
Comes in white only and a pack of 1 dozen. 
12.8 grains