These rollers are very heavy duty and will be the last rollers you need to buy for your garage doors. These rollers are very durable and are made for the toughest of doors. They are also very calm. You will notice a in how and quiet your door is after replacing your old worn out rollers. Suitable for: automatic garage doors, garage door, solid wood garage doors, garage door anti-pinch handcarts, residential garage doors, garage door engineering, remote control garage doors, garage door villa, etc. Specifications: Sealed Ball Bearing Quantity: 11 Pieces Diameter: 10mm (0.39 inch ) Total Length: 105mm (4 inch ) Wheel Diameter: 45mm (1.78 inch ) Wheel Thickness: 11mm (0.43 inch ) colour: white Material: nylon + metal size: 46x120mm Package Contents: 4*Garage Door Wheels Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.