28B B Series Roller Chain 1.material:40MN/A3 2.pitch:44.450mm 3.plate thickness:7.5/ ... 6.0mm 4.surface treatment:heat treatment 28B B Series ... chains: 428SO,520SO,525SO,530SO3. Roller chains: A series and B series4. Silent chains: SC3,SC4,SC5,SC6,SC8,SC105. ... PIV chains: A0,A1,A3,A4,A5,A66. O-ring chains and xw-chains: 420 ...