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.