Easy to install: You need to put the spool in the right direction and close the cap to fix it. The reels work well once you get it right.<br> Auto Feed: It feeds automatically when needed, which is achieved by centrifugal force, so please note that the auto feed should be in high speed<br> Pre-loaded spools: Manual winding usually causes uneven surface, it makes the trimmer difficult to work, pre-installed spool is more convenient, protects your Ryobi cordless trimmers and extends the lifespan of your machine.<br> ryobi trimmer wire spool works with the following string trimmer models:<br> 18V -OLT1825, OLT1825M, OLT1830H, OLT1831, OLT1831H, OLT1831S, OLT1832<br> P2000, P2001, P2002, P2003, P2004, P2005, P2006,P2200<br> RLT1825, RLT1825Li, RLT1825LL13, RLT1825M13, RLT1830H13<br> RLT1830H15, 25, RLT1830Li , RLT183113, RLT183115<br> RLT183125, RLT1831H20, RLT1831H25, RLT1831H25<br> RLT1831H25PK, RLT183213, RLT183220, RLT183225RLT183225PK,<br> 24V - RY24000, RY24020, RY24021 , RY24200<br> 40v - RY40001, RY40021, RY40200, RY40201, RY40210, RY40210A