BDS accessory vee grooves are made from billet 6061 aircraft aluminum and T6 heat treated for durability. The vee groove pulleys are sold individually and are designed to stack together along witht he pulley spacers to allow the use of multiple vee grooves and special spacing, when required. The vee grooves are .700" wide with a diameter of 6.25". The marine 3V pulley has a 5" diameter and is 2 1/4" deep. It is also drilled with a dual pattern stock and aftermarket.