Musiclily Vintage Roller Guitar String Tree Guides Retainer for Fender Strat Stratocaster Tele Telecaster Electric Guitar, Chrome(Pack of 4) Improves performance for your guitars,it stress on your strings which allows the guitar to stay in tune longer This also prevents wear and tear on the strings which results in longer string life Base is 6mm wide x 11.5mm length;Roller width is 10mm;Roller diameter is 5mm; String Spread(center to center) is 7 mm Metal made, come with mounting screws, ready for use. Package Included: 4 pcs Guitar String Trees