... 4.ISO9001:2008 Detailed Production Description(16B-2) durable duplex roller chains &chain manufacturer B series1)material : 40mn2)pitch : 25 ... roller chains: A series(12.7-63.5mm pitches),B series (9.525-50.8mm pitches)and their ... heavy series products(19.05-44.45mm pitches)2)motorcycle chains :428,428H,530,530H,630,630H3) ... roller chain attachments:A-1,A-2.K-1,K-2,SA-1,SA-2,SK-A,SK-24)double pitch ...