Are you having P.E. lesson and are you looking for place to hide your valuable items like ring, earrings, necklace or any other small valuables? Then you just found the perfect solution. This is safe protected by a four-digit code that you can create using numbers 1-7. The default numbers are set to 1,1,5,6, but you can modify it with your own numbers, or even with for example letters. Its designed for maximal protection, so the alignment must be precise, but if this feature would annoy you, you can just use sand paper or file to make the holes bigger. PLA filament is enough, but if you want, you can use any stronger filament. If you want, you can put screw to the top of the lock as I did to make using this lock even easier. After assembling, just glue the upper part to the rest of the lock and you're done.