The Pinnacle of Precision & Performance™ Altra Reinforced Concentric Outset System (A.R.C.O.S.) fits the Altra Arrows 166 Shafts and are machined out of Ti5 titanium for unmatched durability and performance, with optimal fit options.The insert secures into the arrow shaft at a depth of 0.875", while the outsert then threads directly onto the insert and encapsulates the leading end of the arrow at 0.43" creating unmatched durability. Essential rubber O-rings come pre-installed on the insert within the A.R.C.O.S., as they aid in locking the outsert in place which reduces vibration and improves concentricity between the outsert to the insert for a more precise arrow set up and down range accuracy. Features: Accepts micro FMS insert weights Available in four sizes - 250, 300, 350, & 400 spine Weight: 59 grain outsert weight, 72 grain total when used with 7075 aluminum insert Quantity: 12-pack
