Usage Tips:Possess Sealed 6200ZZ Ball BearingFits residential and commercial doors comes in 2 inch trackRate of one is 150 lbs at the rate of 100,000 cyclesNylon lessens the noiseHighly durableThe nylon shells around wheels smooth and quiet operationSpecifications: Thickness: 0.48 inch Diameter: 1.8 inch Length: 4.78 inchStem Shaft Length: 4.25 inchShaft Diameter: 0.43 inchcolour:BlackMaterial:Nylon + metalPackage Contents:12 x Garage Door Only the above package content, other products are not included.Note: Light and different displays may the color of the item in the 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.