Holding box/ compartment for secret car backup key

Hello,

Today I share this box I created to held a secondary key in a secret place hidden in a car.

This summer we went to the beach, I went to the sea one afternoon, carrying by mistake my car key in a poket. It got wet with sea water, and after that the car stopped recognizing it! Sad moment, very difficult to resolve.

I created this box, that is to be held by two screws which adjust against nuts that are to be fitted by the sides of the screw holes. It's construction is strong, ment