I currently use a carbon Keybar-style key manager. My car key is too big to fit in, obviously. I have a key ring attached to the bar, which holds the car key. When I leave the house without using my car, that whole thing is a bit big and I'd like to detach the car key. So what I'm looking for is a really clever way to do that. Something that is super small, super strong and never comes loose if engaged, but disconnects in a second if I want it to. Ideas?