Designed to fit on the rear sight track. Comes in a pack of two. Small enough to not add much weight, but works well to remove extra vibration.
8-32 thread size to fit imperial sights such as Sure-Loc, Axcel, Copper John etc.
M4 intended to fit Shibuya, and others with metric thread.
Please check the appropriate thread size before ordering. You are welcome to CONTACT US if you have any queries.