Description:  【Comprehensive Gear Set】: This educational toy set includes a variety of gears such as main shaft gears, single layer gears, belt pulleys, double layer gears, crown gears and worm gears. It also comes with gear racks (2 pieces), gear installation tools (a set of 2 pieces), and 162A umbrella . 【Variety of Sizes】: The gear set features different sizes for each type of gear to cater to various DIY science model making needs. It also includes car axles in lengths of 30mm, 50mm, 70mm and 100mm (2 each) and axle sleeves with holes in sizes of 2mm, 2.5mm and 3mm (2 each). 【Material】: All the components are made from durable PP material that ensures longevity while maintaining lightweight for easy handling. 【Elastic Bands Included】: The package comes with elastic bands in black, blue, white transparent yellow colors ranging from lengths between 30 70 mm to facilitate the assembly process. 【Application】: Used for DIY, the gear set is a good accessory for your toy car, robot and so on. Easy to change if the gear is missing or damaged, as a replacement accessory. Size Chart: Axle Length: 30mm 50mm 70mm 100mm Bushing Hole 2mm, 2.5mm, 3mm Worm Length: 6mm, 8mm Package Includes: 82 Gear Set  Note: Please allow slightly errors due to manual measurement and different monitors.