Graph Tech man-made white TUSQ XL string trees. A perfect option to upgrade the string retainers on your guitar. They will fit on any guitar that uses string retainers and will help improve the tone and tuning performance of your guitar. TUSQ XL is engineered from the same material as TUSQ and is impregnated with PTFE which is five times more slippery than graphite. It has all the tonal benefits of TUSQ, bringing out the hidden harmonics of your guitar all while drastically improving tuning performance. TUSQ XL is consistent from piece to piece, and within each piece, to offer you harmonically rich tones without the problems associated with natural materials.