http://www.microrobo.com/omni-wheels.html Omni Wheel, also known as Poly Wheel, it is similar to Mecanum wheel. Omni wheel are very unique because they are able to move in many directions and it has small discs around the wheel will roll with full force, but will also slide laterally with great ease. It is a method of creating holonomic drive. Omni wheel can either roll like a normal wheel or roll sideway using the rollers. Its rubber rollers offer great gripping.