The RYOBI 2-in-1 String Trimmer head adds versatility to any RYOBI automatic feed string trimmer. With the ability to use fixed line or serrated blades on this trimmer head, you are able to take down thick weeds and heavy vegetation effortlessly. Change between serrated blades or fixed-line tool-free and with ease. For best use of this trimmer head, avoid edging, contact with fencing or walls with the serrated blade.