AR-15 Receiver Link KitHolds Your Upper In Open Position for Cleaning and Service The AR-15 Adjustable Receiver Link is designed to maintain and secure the opened position of your AR-15 upper and lower assembly. The kit comes with one upper link and two threaded lower links (one short, one long) to provide a total adjustment of approx. 3/4". The upper link utilizes an integral pin to engage the upper receiver and the threaded lower portion utilizes the existing lower takedown hole and pin. The short lower link provides a minimum opened position of 1.2" pin to pin, enough room to insert a bore guide, and the maximum opening is 1.5" from pin to pin. The longer threaded link will provide a minimum opening of 1.4" and a maximum opening of 1.8" from pin to pin. All steel construction.