For more information, please contact omniwheel(at)hangfa.com QMA-15 Specifications: Model Number: QMA-15 Diameter: 152.4mm Width: 53mm Number of Rollers: 14 Number of Bearings: 28 Hub Material: steel Roller Material: Rubber Hole size: 20mm Mount: M6*6 Weight: 800g Load Capacity: 40Kg Usage: robotics , omni moving robot platform , scientific research , electric educational robot machine show equipment on stage or show cars wheelchair