$8.98
Pulled from rest, an extension spring stores energy and draws back toward its original length, and at about half a pound this one sits in the mid-size return and tension range rather than among light trim springs. Tightly wound coils resist being drawn apart and deliver steady force across the working stroke, settling a moving part back into position once the load releases.
An extension spring stores energy when it is pulled and pulls back toward its rest length, and this one weighs about half a pound, putting it in the range of a mid-size return or tension spring rather than a light trim spring. Coiled tight so the coils resist being drawn apart, it delivers a steady return force through its working stroke and settles a moving part back to position when the load releases.
Springs of this type fail by fatigue: the steel loses tension over thousands of cycles, coils can take a set, and the return force weakens until the mechanism no longer resets cleanly. Match the free length, wire diameter, and end-hook style to the spring being replaced, since those three dimensions determine both the fit and the tension it delivers.
