"I can share a little more. It appears to be a snatch-release connector, which is often used to safely break away from one piece of equipment to another piece of equipment/ordnance. The aluminium cap is protective to keep the contacts inside free of FOD [Foreign Object Damage] before mating. As someone else posted, it’s for training. Lastly, it’s cadmium (over nickel) plated, so it's best to wash your hands before eating."