PU5x19x7-2RS PU Covered Bearing 5x19x7mm - Sealed - MiniaturePU5x19x7 2RS Polyurethane Rubber sealed Ball Bearing 5mm x 19mm x 7mm 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. PU0519 7 Ball Bearing Deep Groove Ball Bearing Material: GCr15 bearing steel Cover