Features Sealed bearing, small friction, high temperature resistance and low noise. The contact surface of wheel is quiet and comfortable, durable to use. One-piece thickened bracket, it is firm to install. Internal bearing steel ball has high and uniform hardness, good wear resistance, good contact fatigue performance High speed bearings have good performance. Specification: Material: TRE Rubber + Metal Single Load: 50kg Four Maximum Load: 150kg Weight: Approx. 301g / 10.6oz Wheel Diameter: Approx. 50mm / 2.0in Wheel Width: Approx. 18mm / 0.7in Iron Plate Outer Diameter: Approx. 46 * 38mm / 1.8 * 1.5in Mounting Hole Distance: Approx. 36 * 28mm / 1.4 * 1.1in Installation Height: Approx. 65mm / 2.6in Package List: 4Pcs Rubber Casters Package List