This carburetor is a replacement/upgrade for STIHL FS75 FS80 FS85 KM80 KM85 FC75 string trimmers. It includes a tuning kit and an air filter cover. Made from durable aluminum alloy and brass components, it provides precise fuel metering for efficient combustion, helping reduce fuel consumption and emissions. It also improves cold starts, stabilizes idle and RPM, and delivers stronger throttle response and acceleration, restoring engine performance. Key benefits: - Precise fuel metering for efficient combustion and lower emissions - Easier starts, smoother idle, stable RPM - Quick throttle response and improved acceleration - Compact, durable design for reliable field use - Includes tuning kit and air filter cover for easy installation Compatibility and specs: - Fits STIHL FS75 FS80 FS85 KM80 KM85 FC75 string trimmers - Materials: aluminum alloy and brass components - Mounting compatible with standard diaphragm carburetor fittings Use scenarios: - Trimming thick grass or weeds where extra power is needed - Cold starts or high-load trimming in cool weather - Routine maintenance to restore lost power and fuel efficiency