1,Size: Approximately once for each 40-tooth . its inner diameter is about 5 mm, 40 teeth, suitable for most standard 3D printers2,Practical function: Our 3D printer parts can replace damaged parts, make your printer work more efficiently, and improve the performance and reliability of the 3D printer3,Good carrying capacity: The 40-tooth gears of these driving devices are made of high-quality brass, rust-proof and non-corrosive, durable and stable in use, with good carrying capacity, which can improve the working efficiency of the printer.4,Wide compatibility: Our brass extruder gears are easy to install, compatible with CR-10, CR-10S, S4, and most 3D printers.Product name: 40 tooth 3D printer accessory Weight: 5.5g*5pcsPurpose: 3D printer accessories, consumablescolour: brass ColorMaterial: Brasssize: 11x11mmPackage Contents: 5*Printer brass Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.