the"Busted knuckle duster"

I've got a Benz with a Nag, and no dipstick. I bought the tool for checking. Hard to get my head around that one.
Do you have some info on it. Did you get it from dealership? If I even new how far the dipstick went past the tube i could fill it and check it . Nobody knows anything at the dealership around here makes me wonder if they even know how to check them when they come in for service.