The BT51 ACE bracket was designed for the popular A.C.E. Skeleton Stock and provides the means to attach an Accu-Shot PRM style monopod (BT12-QK, BT13-QK and BT31-QK) to your A.C.E. Skeleton Stock. Besides the Picatinny rail for the PRM, the BT51 has two flush cups for attaching slings. The two piece bracket is clamped to the angular tube and is held in place with the four supplied SHCS fasteners. No modification is required. A 5/32 hex wrench is required but NOT included.Ê