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 material.[5][6] The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passing over it. It really is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley for the reason that sprockets have teeth and pulleys are easy.
Sprockets are used 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 monitor, tape etc. Perhaps the most typical form of sprocket may be within the bicycle, in which the 
pedal shaft carries a large sprocket-wheel, which drives a chain, which, in turn, drives a small sprocket on the axle of the trunk wheel. Early automobiles were also largely powered by sprocket and chain system, a practice mainly copied from bicycles.
Sprockets are of varied designs, a maximum of efficiency becoming claimed for every by the originator. Sprockets typically don't have a flange. Some sprockets used in combination with timing belts have flanges to keep carefully the timing belt centered. Sprockets and chains are also utilized for power transmission from one shaft to some other where slippage isn't admissible, sprocket chains getting used rather than belts or ropes and sprocket-wheels instead of pulleys. They could be operate at high speed plus some types of chain are so constructed as to be noiseless actually at high speed.