High-quality materials: Made of ABS and carbon steel, durable, long service life, good stability, impact resistance, cold resistance, and oil resistance. Easy to use: Install the included spring on the spool cover. Insert the spool cover into the bottom slot of the trimmer, then press and turn the spool cover until the lock clicks into place to complete the installation. Sufficient quantity: There are 4 pieces. The quantity of spool cover for brush cutters and 4 spool springs in the package is sufficient for daily use and replacement. Good compatibility: The size of the replacement spool cover is 86 x 34 mm, and the spring size is 23 x 36 mm. They are compatible with most lawn mowers on the market, such as AFS GH400, GH500, GH600, CST1000, CST2000, NST2018, ST7000, etc. Scope of application: The valve core cover is suitable for patios, lawns, decks, gardens, crops, landscaping, landscaping, etc. It is an ideal choice for replacing old or damaged valve core covers and springs. Note: