This is a spare key hider that looks and functions as a hook!  Mount it somewhere on the wall using 2 screws or 2-sided tape, place your spare key in it and hang something from the hook to hide it. Never be locked out again!!

This should be a snug sliding fit and may not need magnets but I included the magnets to give it a little more security. The magnets are 5mm wide by 2mm thick magnets.

200 MEALOS Mini Magnets - 100pcs 3X1mm, 50pcs 4x2mm, 50pcs 5x2mm Neodymium Magnets Rare Earth Magnets - Tiny Thin Magnets for Miniatures Small Model Hobby Crafts - Small Round Little Magnets Assorted : Amazon.ca: Home