Product description:Material: forty five # steelModule: 0.5Number of teeth: 20TTooth thickness: 5.0mmBase thickness: 5.0mmOverall thickness: 10mmTooth tip outer diameter: Ф 11mmBore diameter: Ф 3mm.4mm.5mm.6mmFixed gap diameter: M3Product application: forty five # steel spindle gear, chiefly used for reducer motor spindle gear, various DIY toy models.Package Include:According in your Choose!