he Pinnacle of Precision & Performance™ Altra Reinforced Concentric Outset System (A.R.C.O.S.) fits our Altra Arrows 166 Shafts and are machined out of 7075-T6 aluminum 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: Altra Arrows highly recommends using a foam style arrow target when shooting arrows that have an ARCOS system, as the outserts can get stuck in filler of bag style targets which can damage the insert/outsert system or arrow. Find Assembly Instructions HERE
