TAB sling thing, get them at Nordic Marksman. Slips on your sling and carries a CR2032 and has 2 slots for allen/torx wrenches. I think I have 6 or 7 wrenches and a 2032 stuffed in my precision rifle's sling thing, and one on the Mini 14 with a 2032 for the RMR, torx wrench to change the battery on it if need be and an allen wrench for the irons. They literally make it impossible to get into the field without a battery and a few tools which is good cause I'm an expert in forgetting stuff.