Compatible Models: Compatible with Black Decker String Trimmer: GH900, GH600, LSTE525, LST300, BESTA510, LCC340C, LST522, ST8600, ST7700, ST6600, NST2118, NST2018, NST1118, NST1118, MST912, MTE912, M TE225, LSTE525T Coil Cap Specifications : 4 pieces compatible with Black + Deacker protective caps, cap model: RC-100-P, part number: 385022-03. Compatible with AF-100, AF-100-3ZP, AF-100-BKP, AF-100-2 coil models. Material: ABS material, strength and durability. Easy to install, no complicated processes. Advantage: bayonet design base rests on the original trimmer structure, holds the spool in place, no tools required, just tighten the spool and keep it safe while trimming. Usage: It protects the line and keeps the spool in place.