about this product: Suitable for Black Decker: Suitable for most trimmer models: GL280, GL301, GL425, GL430, GL545, GL555, GLC13, GLC2500, GLC2500L, GLC3000, GL4525, GL.4525S.B, GL5028, GL5028SB, GLC1423L, GLC1825L, GLC3625L, STC1820, STC1815, ST4525, ST5530, STC1820PC, EPC, STC1840, EPC, ST1823 etc. Quality Trimmer Line: 9.15m trimmer thread can enable larger mowing range with 1.65mm diameter, polyamide nylon line is durable and flexible. It is not easy to break, ensuring continuous work. Fast, Clean Cutting: The auto feed system replacement spool makes the tedious work of manually wound spools easier. It uses centrifugal force and aerodynamics to reduce drag and make fast, clean cuts. Perfect Replacement Spool: They are a perfect replacement for most original Black & Decker spool models such as A6481, A6485, AF-100, AF-100-3ZP, AF-100-BKP, AF-100-2. The coil can be inserted and rotated without tools, and the operation is simple. At the same time, damage to the device is avoided and the thread is used optimally. Great Value Set: Package includes 6 replacement grass trimmer spools, 1 replacement caps and 1 replacement springs. Coil cap replaces cap RC-100-P, spring replaces spring RC-100-P. Excellent value.