Feature: 1.Every product has a unique Manufacturing Part Number label on the inner package that proves it has been qualified,which include Part Number,Model Number and inspection date information;2.If you have any questions about the item,please provide us the Manufacturing Part Number for checking,your profits will be guaranteed.3.Made of bearing steel, model is HGH20CA.4.Suitable for HR20 guide rail.5.Applied to machine tools, linear motion, large machinery.Note: 1.Block only, slide rail is NOT included.2.Please allow 1-3mm error, due to manual measurement.specification:Brand name: BQLZRModel: HGH20CAMaterial: Bearing SteelOverall Size: approx 7.8 x 4.4 x 2.5cm/3.07 x 1.73 x 0.98 inch(L x W x H)Block Length: approx 7.5cmWeight: 340gPackage include:1 x Guide Rail Sliding Block