Altra Insert and Outsert .166 250 Spine

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.