This is a genuine Stihl 42831900721 spring housing, an essential component for the recoil starter assembly in various Stihl BG, BR, and SH series handheld power equipment. It is designed to securely hold the starter spring, ensuring proper tension and smooth operation for reliable engine starts. Manufactured to Stihl's original equipment specifications, this part guarantees optimal fit, durability, and performance, maintaining the integrity of your equipment's starting system.