50 series duplex roller ... delivery 4.OEM ok Detailed Production Description50 series duplex roller chains(10A-2R)1)material ... roller chains: A series(12.7-63.5mm pitches),B series (9.525-50 ... .8mm pitches)and their heavy series products(19 ... ,2050,2060,20805)leaf chains:LH series,AL series6)stainless steel roller chains7) ... requirements. 50 series duplex roller chains(10A-2R)ISO9001 ...