The ROTARY Starter Rewind Spring is a replacement part designed specifically for Tecumseh lawn mowers, model numbers HM100, HM70, and HM80. Made by the brand Rotary, this spring is compatible with gas-powered mowers and comes as a single unit in the pack. This high-quality spring ensures smooth and reliable operation of the mower's starter rewind mechanism, allowing for easy and convenient maintenance and repair of your lawn mower.