Specification: Quantity: 10 pcs 200 teeth no perforation 5mm aluminium timing belt idler pulley Colour: metallic Size: height: 8.5mm/0.33inch, width: 18mm/0.7inch, belt width: 6mm/0.23inch, bore diameter: 5mm/0.19inch. Material: high quality aluminium, with surface oxidation treatment, effective anti-rust and anti-corrosion Features: Usage: for GT2 6mm wide synchronous belt. Double bearings:Use high quality motor grade bearings to ensure the machine runs well. Widely used:Used in 3D printers, CNC, milling machines, gear forming machines, drilling machines, CNC machine lathes, gear hobbing machines or other mechanical transmission occasions. Warm tips: All data are measured manually, please understand if there is any error!