This is a set of four stainless steel set screws (2 - 3/16 long and 2 - 3/8" long). These are used to mount ASA's to the bottom of T-Slotted frames
Depending on the ASA used they may go through the bottom of the frame (the longer screws) and lock against the ASA, or they may go through the ASA and lock against the frame (shorter screws).
You can use all 4 screws with some frames and ASA's if you want to really lock the ASA into place so it won't move even in the worst dives).
Depending on the ASA used they may go through the bottom of the frame (the longer screws) and lock against the ASA, or they may go through the ASA and lock against the frame (shorter screws).
You can use all 4 screws with some frames and ASA's if you want to really lock the ASA into place so it won't move even in the worst dives).