Feature:1. Better Design: The multi subdivided circular structure of the 102mm metal omnidirectional wheel enables easy self stabilizing, which ensures smooth running with little vibration.2. Dual Bearings: Each small driven wheel is embedded with miniature bearings, turning the sliding friction into rolling friction to achieve lateral movement with micro resistance.3. Good 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.4. Advanced 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.5. Easy 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.Specification:Item Type: Omni WheelDiameter: Approx. 102mm or 4.02inNumber of Side Wheel on Single Wheel: 9pcsNumber of Single Wheel Bearings: 18pcsBearing Type: Rolling BearingTruckle Material: SiliconeWheel Hub Material: Aluminium AlloyWheel Surface Treatment: Double layer high temperature baking paint. Connection Form: Flat Key or Set ScrewSingle Wheel Load Capacity: Approx. 30 kg or 66.14 lb.Package List:1 x Dual Omni Wheel CombinationNote:Match the appropriate designed size before use.