Material: High quality ABS spool and stable nylon line, are very good for lawn mowing, optimized for optimum and precise trimmers Spool specification: The spools of 30 foot threads are factory wrapped for great feed the portable 0.065 inch diameter cord supports fast cutting and longer life, compatible with original spool models AF-100 and RF-100 Quick and Seamless Cutting: The replacement spool for the automatic feeding system facilitates the tedious work on manual winding spools. It uses centrifugal power and aerodynamics to reduce air resistance and achieve fast, clean cuts. Easy to Use: Replacement Thread Spool Fits GL280, GL301, GL425 , GLC2500, GLC2500, GLC2500L, GLC3000, GL4525, GLC1825N, GLC1425N, GLC1825N, GLC1823L, GLC1825L, GLC3630L, ST5530, ST4525, STC1820 , STC1815, STC1820PC/E PC, STC1840 / EPC, ST1823. Advantage Package: The package contains 8 replacement trimmer spools, 1 replacement replacement cover and 1 replacement spring. The coil cover is replaced by the RC-100-P cap, the spring is replaced by the RC-100-P spring.