The carbon express half-out insert is designed for .203″ Inside diameter or sd shafts. Each half-out insert is built to ensure broadheads spin true through the entire season. The flush fit to the outside of the arrow shaft eliminates hang-ups when removing the arrow from the target & the additional weight forward delivers increased accuracy and penetration on shots. The new aluminum half-out insert is made of 7074 aircraft aluminum for lighter weight design but incredible durability. Standard half-out insert is made of premium steel and provides more penetration.