Introduction： The omni-wheel has a big core wheel, along which peripheral there are many additional small wheels that have the axis perpendicular to the axis of the core wheel. The core wheel can rotate around its axis like any normal wheel, but now that there are additional wheels perpendicular to it, the core wheel can also move parallel to it's own axis. A robot that uses omni-wheels can move in any direction, at any angle, without rotating beforehand. Features: Omnidirectional transfer ability High-quality rubber wheel, great ground traction Specification: Outer diameter: 48mm Inner diameter: 4mm Thickness: 20mm Material: Plastic & Rubber