Single precision bearing helps the wheel roll mute & smoothly. The caster can rotate at ease, thanks to it's double bearing raceways. Plastic bearing hubs help prevent dust and silk intrude inside the core - thus increase its lifetime.
Cushion grey PU tread is non-marking material. This caster will leave any mark on your clean & shiny floor. The PU wheel is also resist to water, oil, grease and some light chemical.