Description Pack of 20 assorted plastic gears Modulus 0.5 Bore Diameter: 1.9mm Compatible with 2mm shaft Suitable for hobbies, models, science and other projects The Motorizing Pinion Gear Set (20pk) is a pack of assorted plastic gears suitable for hobbies, models, science and other projects. View more What's Included 1 x Motorizing Pinion Gear Set (20pk) Specifications Modulus 0.5 Bore Diameter 1.9mm For 2mm shaft