Features:- Made of high-quality material, durable and sturdy, anti-scratch and anti-corrosion.- Easy to install, no tools required. Just snap in place over spool line, convenient to use.- Protect your line and keep it in place on your string trimmer.Specifications:Color: As shownMaterial: PlasticHow to Replace the Thread Spool:- Remove the battery from the device- Open the bobbin case by pressing the two release buttons on the bobbin case at the same time- Take off the cover of the bobbin case and take out the bobbin- Push the thread ends of the new thread spool out of the slots in the trimmer spool- Insert the new bobbin into the bobbin case so that the arrows indicating the direction of travel are visible on the bobbin after it has been inserted- Then put .