Double pitch sprockets have rollers of the same diameters and widths as American standard roller chains of one half the conveyor chain pitch. Engaged by every other tooth, double duty sprockets have two teeth per chain pitch. During each revolution only half the teeth function effectively. Sprockets with odd numbers of teeth will allow any given tooth to engage only on every other revolution, automatically increasing sprocket life. Double duty sprockets with even number of teeth may be manually advanced one tooth periodically to increase sprocket life. Martin Roller Chain Sprocket, Type B Single Strand Double Pitch Reboreable, 1 to 2-3/4 in Bore, 8.2 in OD, #2080 Chain, 24 Teeth, 2 in Pitch, 7.727 in Pitch Diameter, 4-1/4 in Diameter Hub, 1-3/4 in Length Through Bore, Steel