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 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 for the reason that sprockets have tooth and chain sprocket pulleys are even.
Sprockets are found in bicycles, motorcycles, vehicles, tracked automobiles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or even to impart linear movement to a monitor, tape etc. Maybe the most common form of sprocket may be found in the bicycle, where the pedal shaft carries a sizable sprocket-wheel, which drives a chain, which, in turn, drives a little sprocket on the axle of the trunk wheel. Early automobiles had been also largely powered 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 possess flanges to keep carefully the timing belt centered. Sprockets and chains are also used for power transmission from one shaft to another where 
slippage isn’t admissible, sprocket chains becoming used instead of belts or ropes and sprocket-wheels instead of pulleys. They can be run at high speed plus some kinds of chain are so constructed as to be noiseless also at high speed.