Professional design: The string trimmer full harness is specifically manufactured for STHIL FS and Kombi KM series trimmers, ensuring a fit and compatibility. OE reference number: Please verify the OE number 4119 710 9001 to ensure the correct replacement part, providing convenience and flexibility. Fatigue reducing function: The backpack shoulder strap design distributes weight evenly across the upper body, reducing fatigue on the shoulders and body during operation. Adjustable straps: The weed eater strap is designed for righthanded users, and the straps are adjustable. Use scenarios: Extended trimming sessions on large residential or commercial properties, where comfort and weight distribution help reduce fatigue. Professional landscaping crews using STIHL FS or Kombi KM trimmers, benefiting from reliable compatibility. Trimming around obstacles and along fence lines or edging, where balanced weight improves control and reduces strain.