Product Name: Convex Step Gear Speed Reducing Motor Metal Gear Material: forty five steel Modulus: 0.5 Number of teeth: 20 Teeth Tooth thickness: 5.0mm Base thickness: 5.0mm Overall thickness:10mm Tooth height outer diameter:11mm Inner diameter of enamel hole:3mm.4mm.5mm.6mm Fixed hole diameter:M3 Product use: 45 metallic spindle gear, chiefly used for reducer motor spindle gear, a wide range of DIY toy model. Send 1 x M3 machine meter screw according to gear. Send 1 wrench in keeping with order. Pack Quantity: 1Pcs