These adapters are made to glue into carbon and aluminum shafts so you can use 5 degree taper glue on broadheads and points. Sizes available: 5/16" long: these fit GT-Express, Gold Tp, Easton, Gametracker, PSE & Carbon Tech. Also avaialable while supplies last: Nitro/Grizzly, 2216, 5/16 & 2315. Sold by dozen. 5/16 available by the 100. Please specify.