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 should never be meshed together straight, and differs from a pulley for the reason that sprockets have tooth and pulleys are simple.
Sprockets are found in bicycles, motorcycles, vehicles, tracked vehicles, and other machinery either to transmit rotary movement between two shafts where gears are unsuitable or even to impart linear motion to a track, tape etc. Probably the most typical form of sprocket could be within the bicycle, where the pedal shaft bears a large sprocket-wheel, which drives a chain, which, subsequently, drives a little sprocket on the axle of the rear wheel. Early automobiles were also largely powered by sprocket and chain mechanism, a practice mainly copied from bicycles.
Sprockets are of varied designs, a maximum of efficiency getting claimed for each by the originator. Sprockets typically don’t have a flange. Some sprockets used with timing belts possess flanges to keep carefully the timing belt centered. Sprockets and chains are also utilized for power transmission in one shaft to another where slippage isn’t admissible, sprocket chains being used instead of belts or ropes and sprocket-wheels instead of pulleys. They could be operate at high speed plus some forms of chain are so constructed as to be noiseless also at 
high speed.