Fitment: For FS38 FS45 FS46 FS55 FS55C FS55R HL45 FC55 KM55 KM55C KM55R trimmers. Replaces 4140, 182, 1000. Responsive speed control: This throttle trigger provides precise control over engine speed, allowing smooth acceleration or deceleration while trimming or cutting. Ideal for adjusting power output based on grass height or terrain. Durable high-stress design: Made from reinforced plastic or alloy materials, this throttle lever resists wear, vibration, and heat. Designed for demanding outdoor use, it ensures long-lasting performance in both residential and commercial garden tools. Comfortable ergonomic grip: The contoured shape fits naturally in the hand, reducing fatigue during extended use. This grass trimmer throttle control offers smooth movement and a firm feel, giving users confidence during every operation. Use scenarios: - Variable terrain and tall grass: Quickly adjust throttle to maintain consistent cutting quality without overworking the engine. - Edging and edging work: Use precise throttle response for clean cuts along sidewalks, fences, and landscaping features. - Extended professional sessions: Ergonomic grip and smooth throttle action reduce hand fatigue during long trimming jobs.