1Better Design: The multi subdivided circular structure of the 102mm metal omnidirectional wheel enables easy self stabilizing, which ensures smooth running with little vibration. 2Dual Bearings: Each small driven wheel is embedded with miniature bearings, turning the sliding friction into rolling friction to achieve lateral movement with micro resistance. 3Good Material: Using high quality silicone material, the drum shaped small wheel has strong grip, which can run silently on wood, ceramic tiles, carpets and many other surfaces. 4Advanced Work: Treated with high temperature baking varnish, the omni wheel with aluminium alloy hub is very is beautiful, and also has excellent durability for long term use. 5Easy to Install: Comes with a light weight and a compact size, the omnidirectional wheel can be easily installed on robot, toy car, etc. for more DIY entertainment. Item Type: Omni Wheel Diameter: Approx. 102mm / 4.02in Number of Side Wheel on Single Wheel: 9pcs Number of Single Wheel Bearings: 18pcs Bearing Type: Rolling Bearing Truckle Material: Silicone Wheel Hub Material: Aluminium Alloy Wheel Surface Treatment: Double layer high temperature baking paint.Connection Form: Flat Key or Set Screw Single Wheel Load Capacity: Approx. 30 kg / 66.14 lb 1 x Dual Omni Wheel CombinationMatch the appropriate designed size before use.