Specification Brand : 和気産業 BulletPoint1 : Materials: Frame: Iron, Wheel: Iron casting BulletPoint2 : Load Capacity: 55.1 lbs (25 kg) per 2 BulletPoint3 : Nails: #13 x 19 BulletPoint4 : Note: For the old nail holes, please finely shave chopsticks, etc., and apply a woodworking bond to fill the wood BulletPoint5 : Note: Although it is strong and strong, it is not suitable for water because it is made of iron Color : Black CompatibleWithVehicleType : Passenger Car CompatibleWithVehicleType1 : Truck CompatibleWithVehicleType2 : SUV ExteriorFinish : Polyurethane ExternallyAssignedProductIdentifier : 4903757144262 ExternallyAssignedProductIdentifier1 : 0616639519723 ExternallyAssignedProductIdentifier2 : 616639519723 HoleCount : 5 ItemDisplayWeight : 106.7 grams ItemName : WAKI Roller Door Wheel Flat 30mm ItemOffset : 1 millimeters ItemPackageDimensions_Height : 1.7 centimeters ItemPackageDimensions_Length : 10.2 centimeters ItemPackageDimensions_Width : 5.2 centimeters ItemPackageQuantity : 1 ItemShape : Round ItemTypeKeyword : drive-rollers LoadCapacity : 25 kg Manufacturer : 和気産業 Material : Iron Material1 : Rubber Material2 : Polyurethane ModelName : Aircraft Wheel ModelNumber : SH-426 NumberOfItems : 1 NumberOfWheels : 4 PartNumber : SH-426 PitchCircleDiameter : 5 inches ProductDescription : What's the difference between the two: The higher priced ones are made using time proven vulcanized rubber to 70 duro. These wheels were made with 70 duro hardness polyurethane. If I gave one each of them to you I'm fairly certain you would not be able to tell the difference. In use, polyurethane will start to melt around 185F degrees. If you run them that hot, you'll have problems with the bearings (on both the rubber and poly wheels) also. Keep the temp down and these will work just fine and you'll save 1/3 of the cost of rubber wheels. NOTE: The precision fit of the small wheel holder attachment is very high. I've hand test fit each one of these custom made poly wheels into an attachment fixture. Expect these to be a very snug fit. If they just don't fit in your fixture, you may have to move one of the press fit bearings slightly (in or out) using a punch and hammer ProductSiteLaunchDate : 2015-03-13T06:05:03.372Z Size : 30mm Style : Flat SupplierDeclaredDgHzRegulation : not_applicable UnitCount : 1 WebsiteShippingWeight : 8 pounds