Sprocket : standard sprocket :06B-48B , ASA40-ASA240 , Simplex ,duplex ,triplex .Non-standard sprocket : manufactered by drawing Sprocket : standard sprocket :06B-48B , ASA40-ASA240 , Simplex ,duplex ,triplex .Non-standard sprocket : manufactered by drawing . Mufactured by Hangzhou Vision Chain Transmission co.,ltd