For best stiffness print the parts with 3 outlines, 0.2mm layer height, minimum 3 top and bottom layers and 25% honeycomb/ 3d-honeycomb infill.

You will also need:

• A nail with 1mm diameter, where you cut a piece of 7.5mm out. This connects the inner bolt with the smaller latch.
• A short spring out of a pen which moves the smaller latch.
• A long spring out of a pen which moves the larger locking latch. This spring needs to be stretched, so that it still has tension when retracted.
• Four countersunk screws M3 x 12mm which hold the upper and lower part together.
• Teflon grease for the moving parts.

If you need this thing for the opposite direction, just mirror the upper and lower part in your slicer.