Description<br />Spring :<br />Industrial Grade Steel<br />Heat Treated<br />Solid Machined Construction<br />Black Oxide Finish<br />Tube:<br />Tight Tolerance Control With Zero Gap Fitment With Butt Stock And Receiver<br />T6 6061 Aircraft Aluminum Construction<br />Matte Black Anodizing with Type III Anodizing<br />With Buffer Castle Nut End Plate<br />5 Item kit includes: 3 oz weight・ commercial spec rod cylinder・ end plate・ spring・ latching nut.