A helical shaped closely coiled wire that offers resistance when extended, and gets back to its original shape is called an extension spring. Extension springs are helical wound springs that are so closely coiled together to create initial tension in the coils. This initial tension creates resistance against the force applied to its ends for extension. The initial tension helps determine how closely and tightly the coils are attached. An extension spring has end coils, hoops, or loops that are usually present at both ends to help in the extension of the spring when any other object is attached to it. These springs are good at absorbing and storing energy and also to resist a pulling force.Extension Springs are manufactured from 0.20mm to 10mm Wire Dia.