birth end Item particulars Name: 1pcs Type: LM35UU or LM40UU or LM50UUInside diameter: 35mm or 40mm or 50mm Item including 1pcs plastic linear ball baearing Features: Easy maintenance, can be utilized in liquid, dusty occasions .... Advantages: no card ball, corrosion resistance, dirt resistance, put on resistance, lubrication-free, mild weight, non-magnetic, insulationPlastic linear bearing is a self-lubricating linear movement system, which is the most important distinction with the steel linear bearing steel linear bearing is rolling friction, bearing and cylindrical shaft is the point of contact, so here's compatible for low-load high-speed movement; and Plastic linear bearings are sliding friction, surface touch between the bearing and the cylindrical shaft, so this compatible for high-speed low-speed movement. Plastic linear bearings without a particular shaft bearings; can undergo a better load than the metallic bearings, yet due to the motion between the bearing and the shaft is a sliding friction, so plastic linear bearings speed is field to certain restrictions; resistance than the metallic directly line Bearings to be large; yet its motion noise than the metallic linear bearings low, particularly in the case of high-speed, plastic linear bearing noise with speed is awfully small. Due to its internal design with chip flutes, plastic linear bearings allow use in functions with high dirt and dirt automatically carries the bearing body friction surfaces from the flutes during movement; plastic linear bearings additionally allow use during use Cleaning, can even be used for long-term liquid operation. '