A sprocket[1] or sprocket-wheel[2] is a profiled wheel with tooth, or cogs,[3][4] that mesh with a chain, chain sprocket monitor or other perforated or indented materials.[5][6] The name ‘sprocket’ applies generally to any wheel upon which radial projections engage a chain moving over it. It really is distinguished from a equipment in that sprockets are never meshed together straight, and differs from a pulley in that sprockets have teeth and pulleys are simple.
Sprockets are used in bicycles, motorcycles, vehicles, tracked vehicles, and other machinery either to transmit rotary movement between two shafts where gears are unsuitable or to impart linear movement to a monitor, tape etc. Maybe the most common form of sprocket could be found in the bicycle, where the pedal shaft carries a large sprocket-wheel, which drives a chain, which, in turn, drives a small sprocket on the axle of the trunk wheel. Early automobiles had been also largely driven by sprocket and chain mechanism, a practice largely copied from bicycles.
Sprockets are of varied designs, no more than efficiency being claimed for each by 
the originator. Sprockets typically do not have a flange. Some sprockets used with timing belts have flanges to keep the timing belt centered. Sprockets and chains are also utilized for power transmission from one shaft to another where slippage is not admissible, sprocket chains being used rather than belts or ropes and sprocket-wheels rather than pulleys. They may be run at high speed plus some types of chain are so built as to be noiseless even at high speed.