Feature: ColorOrange Nameplastic belt pulley Size16.8mm diameter, 1.95mm aperture, and it is fit for 1.7mm width belt. The motor shaft diameter is 2mm. It can be connected with Motor axle diameter 2.0mm . Wonderful accessories for DIY RC Model, such as RC airplane toy ,RC helicopter, toy car and so on. Packing list 100 X Orange plastic belt pulley