... B series roller chainsSpecification:1. Simplex: 04B-1, 05B-1, 06B-1, 08B-1, 10B-1, 12B-1, 16B-1, ... 20B-1, 24B-1, 28B-1, 32B-1, 40B-1, 48B-1, 56B ... -2, 10B-2, 12B-2, 16B-2, 20B-2, 24B-2, 28B-2, 32B-2, 40B-2, 48B-2, ... -3, 10B-3, 12B-3, 16B-3, 20B-3, 24B-3, 28B-3, 32B-3, 40B-3, 48B-3, ... DIN 8187 standards.Color: blue, black, yellow and natural industrial transmission chain (B series)