A garage door spring or torsion spring system which counterbalance the weight usually consist of one or maximum two very tightly wound up springs on an iron shaft with cable drums at both of its ends. 
We have in-stock, standard or high-cycle, precision manufactured garage door torsion springs in a multitude of sizes and materials types for anyone looking to repair/replace their garage door springs. Did you know that torsion springs account for over 95% of the lift that is needed to raise a garage door? Because of this continual stress, torsion springs typically only last for 10,000 cycles from the original door producer.