Why mess with winding line. This value-pack of 3 pre-wound spools is a simple and convenient solution for your Ryobi cordless trimmer. Just pop a new pre-wound spool in your Ryobi trimmer, and you're ready to get back work. This quick, easy solution is ideal for all Ryobi cordless trimmers 18-Volt, 24-Volt and 40-Volt.