thompson traveling tractor worm gear set. the worm wheel is in 3 pieces that snap together. I did this so I could try different materials on the gear without reprinting the whole thing, and also so it could be printed without supports. They worked fine on my printer (Anycubic mega) with a fast print at .03 layer height, with a .06 nozzle. pictured is a set with PETG Clear, PETG red, and White is ABS.