This is a derivative of the Safe Box by BLINCOLN. I added a coinslot that is sized to take coins the size of quarters or smaller. I also added engraved text on the top surface. Use it for your bitcoins and other loose change. Caution, I am in the process of printing to verify fit as when I imported it for editing, the dimensions were scaled to inches and I had to scale it back to mm.Per BLincoln..."Print at fine resolution. Carefully push the two box halves to close the box until the hinge breaks free of any stuck plastic and moves freely. Print two dials and two rods and place one dial on each rod. The flat surface on the rod closest to the dial defines the lock open position - choose this to match your favorite code. There is actually a small 16-facet part of the rod (yes, very close to completely round) and this is where the dial should be (the inside of which is also 16-facet). Do not forget the correct key. It will probably take you up to 60 seconds to retrieve it otherwise."