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 passing over it. It is distinguished from a equipment in that sprockets are never meshed together directly, and differs from a pulley for the reason that sprockets have teeth and pulleys are smooth.
Sprockets are found in bicycles, motorcycles, vehicles, 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 track, tape etc. Maybe the most common form of sprocket may be found in the bicycle, in which the pedal shaft bears a huge sprocket-wheel, which drives a chain, which, subsequently, drives a little sprocket on the axle of the rear wheel. Early automobiles were also largely driven by sprocket and chain system, a practice mainly copied from bicycles.
Sprockets are of varied designs, no more than efficiency becoming claimed for every by the originator. Sprockets typically do not have a flange. Some sprockets used in mixture with timing belts possess flanges to keep carefully the timing belt centered. Sprockets and chains are also used for power transmission in one shaft to another where slippage is not admissible, sprocket chains getting used instead of belts or ropes and sprocket-wheels rather than pulleys. They could be operate at high speed and some types of chain are so built concerning be noiseless also at high speed.