Over the years， we‘ve heard all kinds of feedback from our customers. Along with the feedback， we heard a common remark: “when I go back to get another spool…” But why should you have to go back for a spare spool? The Onboard Spool Holder is designed to attach to the shaft of your Worx Line Trimmer and hold one of our standard-size spools (WA0010， WA0004) where you need it – on the trimmer! Store an extra spool right on hand so you don’t have to go back inside if the spool in your trimmer runs out. If you can use Velcro， you can use the On-Board Spool Holder. First， open the Velcro and release it from the rectangular link. Wrap the strap around the shaft of the trimmer wherever you find it most convenient. Thread the strap back through the rectangular link and press the strap down to the other half of the Velcro. Snap in an extra spool. That’s all there is to it! The Onboard Spool Holder is compatible with any trimmer， but keep in mind， only the standard spools (WA0004 and WA0010) will fit in the holder. If your trimmer uses either of these types of spools， the Onboard Spool Holder is going to work for you.