8Pcs GT2 Pulley 40 Teeth 5mm Bore 5M Belt For 3D Printer RepRap PrusaGT2 Pulley:Teeth: 40Groove width: 16mmBore: 5mmFlange: DualMaterial: AluminiumGT2 Belt:Pitch: GT2Width: 6mmLength: 5MFeature:GT2 timing belt and compatible pulley (GT2 pulley) are popular choices for RepRaps and RepStraps.The GT2 series of belts are designed specifically for linear motion.They use a rounded tooth profile that guarantees that the belt tooth fits smoothly and accurately in the pulley groove、 so when you reverse the pulley direction、 there is no room for the belt to move in the groove.For best performance you want at least 6 teeth in contact with the pulley at any given time. That minimizes the chance of the belt slipping、 and helps reduce backlash even further.Package includes:1 x GT2 Belt8 x GT2 Pulley16 x Screws1 x Wrench (As Pictures)