This tool is for the Waterproof Ultima System.  It's used to remove the gloves and to disassemble the system.  Super handy to have several of these with your gear.  One of these comes with your Ultima system…. you're going to lose it.  You might have already lost it and that is why you are reading this.  Buy a couple of these.  Mike drills a hole in the end and ties a loop of line on it and clips it into his drysuit pocket.  Should you do what Mike does?  …generally NO! but in this case, he is on to something.