A sprocket[1] or sprocket-wheel[2] is a profiled wheel with tooth, or cogs,[3][4] that mesh with a chain, monitor or other perforated or indented material.[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 smooth.
Sprockets are found in bicycles, motorcycles, cars, tracked automobiles, and other machinery either to transmit rotary movement between two shafts where gears are unsuitable or even to impart linear movement to a monitor, tape etc. Maybe the most typical form of sprocket may be found in the bicycle, where the pedal shaft carries a big sprocket-wheel, which drives a chain, which, subsequently, drives a small sprocket on the axle of the trunk wheel. Early automobiles were also largely powered by sprocket and chain system, a practice mainly copied from bicycles.
Sprockets are of varied designs, a maximum of efficiency getting claimed for every by its originator. Sprockets typically don’t have a flange. Some sprockets used with chain sprocket timing belts have flanges to keep the timing belt centered. Sprockets and chains are also used for power transmission in one shaft to some other where slippage is 
not admissible, sprocket chains being used instead of belts or ropes and sprocket-wheels rather than pulleys. They could be run at high speed and some kinds of chain are so constructed as to be noiseless actually at high speed.