A sprocket[1] or sprocket-wheel[2] is a profiled wheel with teeth, 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 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 even.
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 to impart linear motion to a monitor, tape etc. Probably the most typical form of sprocket could be found in the bicycle, in which the pedal shaft bears 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 system, a practice generally copied from bicycles.
Sprockets are of varied designs, a maximum of efficiency being claimed for each by its 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 utilized for power transmission in one shaft to another where slippage is not admissible, sprocket chains becoming used instead of belts or ropes and sprocket-wheels rather than pulleys. They can be operate at high speed and some forms of chain are so built concerning be noiseless actually at high speed.