PACKAGE INCLUDES: This stihl trimmer parts set contains 1 thrust washer / 1 support plate / 1 collar nut / 1 screwdriver, it does exactly what it is supposed to do and is well constructed. EASY TO INSTALL: Easy to replace the spool on the trimmer with the blade adapter kit. The blades fit tightly with little to no vibration. Also, you can use it with Youtube videos. FIT: No OEM parts, only replacement parts, guarantee durability and performance and save money. Thrust washer: 4130-713-1600; Rider plate: 4126-713-3100; Collar nut: 4126-642-7600. Good Compatibility: Helps install Husqvarna weed trimmers. Compatible with the following models: Stihl FS40C, FS55R, FS56R, FS36, Sarlo SS-18, FS81, FS 80, FS 81, FS 85, FS90, FS 100, FS 110, FS120, FS200, FS250. Premium Quality: The blade adapter set is made of high-quality stainless steel material, which is sturdy and durable. Due to the high quality, this set will not rust and crack, so you can use this set for a long time.