... black, yellow and natural B series roller chainsSpecification:1. Simplex: 04B-1, 05B-1, 06B-1, 08B-1, 10B-1, 12B ... -1, 64B-1,72B-1.2. Duplex: 05B-2, 06B-2, 08B-2, 10B-2, 12B-2, 16B-2, ... , 72B-2.3. Triplex: 05B-3, 06B-3, 08B-3, 10B-3, 12B-3, 16B-3, 20B-3, 24B-3, 28B-3, 32B-3, 40B-3, 48B-3, 56B-3, 64B-3, 72B-3.Material: alloy ... Color: blue, black, yellow and natural industrial transmission chain (B series)