This is the 2nd order of the quartet puzzle origionally designed by Lykwid of twistypuzzles.com. To complete the puzzle you will need a screw and a nut (The screw needs to be a #4-40 and 1" long. Note, one of the holes for the screw is shallower than the other. This is where the head of the screw needs to be placed or the puzzle will not work).
* I have Lykwids permission to sell the quartet and other versions of it.