Specification:Name: Sprockets Chain GearType: 04CMaterial: 45# SteelSurface Treatment: BlackeningPitch: 6.35mmTeeth: 13 TeethBore: 5/6/6.35/7/8/10/12mm (Round Hole)Bore: 8/10mm(keyway 3mm),10/12mm(keyway 4mm) (Keyway Hole)Application:For use with curler chainsNote:1. The bore of the sprocket is a ending hole, so that you can use it without machining the bore after purchase. Some of the bores have keyways, which are marked within the solutions and might be purchased directly.2. Due to various production batches, the dimensions (such as steps, complete height, top wire, etc.) may perhaps vary slightly, please discuss with the actual product.Package :Packing : Plastic bag / Carton box.Quantity : According for your Choose!