A sprocket[1] or sprocket-wheel[2] is a profiled wheel with the 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 where radial projections engage a chain moving over it. It is distinguished from a equipment in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have the teeth and pulleys are simple.
Sprockets are found in bicycles, motorcycles, vehicles, tracked vehicles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or to impart linear movement to a monitor, tape etc. Probably the most common form of sprocket could be within the bicycle, where 
the pedal shaft carries a huge sprocket-wheel, which drives a chain, which, subsequently, drives a little sprocket on the axle of the rear wheel. Early automobiles had been also largely driven by sprocket and chain mechanism, a practice generally copied from bicycles.
Sprockets are of various designs, no more than efficiency becoming claimed for every by its originator. Sprockets typically don't have a flange. Some sprockets used in combination with timing belts possess flanges to keep the timing belt centered. Sprockets and chains are also utilized for power transmission from 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 could be operate at high speed and some forms of chain are so constructed concerning be noiseless actually at high speed.