Two different designs for replacing aluminum NEMA 17 (5mm) flexible shaft couplers with printed parts. Nominally both designs are 5mm to 5mm Shaft Couplers. The "3 Start" Comes out nice with no supporting material. Additional parts required: 3mm set screw for D-Shaft end (fit is tight, set screw optional). 3mm x 12-16mm screw and nut for clamping end. The "16 Pitch" has built in support material that can be snipped out easily with pliers,x-acto,diagonal cutters,etc... Additional Parts Required: 3mm x 16mm screws (Qty 2) 3mm nuts (Qty 2) 3mm washers (Qty 2, optional)Print both vertically, no support material required. If printing one at a time slow print speed down so that each layer takes 15-30 secs minimum.