A selection of 34 kinds of gear, Containing the different worm, straight teeth, the spindle gear, crown gear, double reduction gear. And many more as shown in photoApplications DIY small production, product design, mechanical model samples science, necessary gear parts package.The Bore size of 2A is 1.95MM, 2B is 2.05MM.- Including gear, rack, pulley, belt and other transmission parts of a total of 34 plastic gear combination, to meet your DIY needs.- Accessories range, a research laboratory, science activities, and other essential personal diy model of mechanical parts! Package Included:1pcs Plastic Gear Set (34 Kinds)