Product Description: Advantages: 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.Every set includes 4 pcs Ball Bearing, 4 pcs Optical Axis and 8 pcs Vertical Linear Rail Support Guide.4.They fit for various types of electronic equipment / guide rod, drive shaft and prop.5.Good wear resistance and strength, high accuracy, hard to rust.6.Has good performances, low friction coefficients and long usage spans. Color: SilverWeight:830gAccessory:4 pcs 8x34.5mm Steel Linear Motion Ball Bearing8 pcs 42x24x10mm Vertical Aluminum Rail Support Guide4 pcs 8x300mm Steel Linear Shaft Optical AxisPackge include:set of Vertical Linear bearing slide set(16pcs)Q:How can I know more details of each Accessory? A:Welcome to visit our shop to see the related items with corresponding keywords.