Martin double strand solid construction sprockets have proper spacing between chain rows. The sprockets are manufactured from high carbon steel. Martin does not stack \"A\" plates on multiples, but instead Martin machines teeth after the chain rows are already in place. These plain bore sprockets can easily be bored to a metric or standard size to fit your application. Keyways, set screws and hardened teeth are quick alterations that can be made. Martin Single Roller Chain Sprocket, Double Strand Solid Stock Bore Type B, 1 in Bore Dia, 4.657 in Outside Dia, 80-2 Chain, 13 Teeth, 1 in Pitch, 4.179 in, 3.15 in Hub Dia, 2-1/2 in Length Through Bore, Steel