Mechanical Lock - One of the creative DIY Rubber-band powered Mechanical Working Lock makes an engaging Utility toy for kids which keeps them wondering with its unique functioning. A DIY Mechanical Lock comes with 1 set of working DIY lock & 2 DIY keys (1 working & 1 non-working). Funvention is introducing a unique 3D Puzzle Assembly Model with working lock mechanism which comes in the form of a puzzle, kids can assemble it, paint it with any colors to make it personalised and unique. Assemble these laser cut pieces together to make your own working lock & keys! These pieces are fine cut which allows glueless assembly. Still, you can add some glue dots to the joints to make it permanent assembly.