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 passing over it. It really is distinguished from a gear in that sprockets are never meshed together straight, and differs from a 
pulley for the reason that sprockets have teeth 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 movement to a monitor, tape etc. Perhaps the most common form of sprocket may be within the bicycle, in which the pedal shaft bears a big sprocket-wheel, which drives a chain, which, subsequently, drives a small 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 various designs, a maximum of efficiency being claimed for each by its originator. Sprockets typically don’t have a flange. Some sprockets used in mixture with timing belts possess flanges to keep the timing belt centered. Sprockets and chains are also used for power transmission from one shaft to some other where slippage isn’t admissible, sprocket chains being used instead of belts or ropes and sprocket-wheels instead of pulleys. They can be operate at high speed plus some types of chain are so constructed as to be noiseless even at high speed.