I have a leak in my shower that comes from the hand held shower head. It seems to leak from hot water. It is a 3 handle faucet that says Gerber on the piece that comes off the handle. I have done some research and I think I may need to change the cartridge but I dont know which one is the right one. I am hesitant to mess around with it due to age (and my wife telling me not to) and was wondering if there is a way to identify it by a photo. I appreciate any help the forum is able to provide.