PU10X40X10-2RS PU Covered Bearing 10x40x10mm - Sealed - MiniaturePU10X40X10 2RS Polyurethane Rubber sealed Ball Bearing 10mm x 40mm x 10mm Polyurethane ( PU) is a new type of polymer composite materials between rubber and plastic, offering higher load bearing capacity compared to plastic, polyurethane offer superior impact resistance, while good mechanical properties. Polyurethane have better abrasion and tear resistance than rubber. PU10x40x10 2RS Ball Bearing Deep Groove Ball Bearing Material: GCr15 bearing steel