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 materials.[5][6] The name ‘sprocket’ applies generally to any wheel upon which 
radial projections engage a chain moving over it. It is distinguished from a equipment in that sprockets are never meshed together straight, and differs from a pulley for the reason that sprockets have the teeth and pulleys are soft.
Sprockets are used in bicycles, motorcycles, cars, tracked vehicles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or to impart linear motion to a track, tape etc. Perhaps the most typical form of sprocket could be within the bicycle, in which the pedal shaft carries a big sprocket-wheel, which drives a chain, which, in turn, drives a little sprocket on the axle of the rear wheel. Early automobiles had been also largely powered by sprocket and chain mechanism, a practice largely copied from bicycles.
Sprockets are of varied designs, a maximum of efficiency being claimed for every by the originator. Sprockets typically do not have a flange. Some sprockets used with timing belts have flanges to keep carefully 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 instead of pulleys. They can be operate at high speed and some types of chain are so constructed concerning be noiseless actually at high speed.