Designed to boost guitar performance,�TUSQ XL�is precision engineered and specially formulated�to bring out the hidden harmonics and richness in every note. TUSQ XL is based on the highly resonant�TUSQ man made ivory and impregnated with PTFE, the slipperiest substance on earth, to improve the tuning performance of the guitar. TUSQ XL Sleek String Trees. Two long, one short and with chrome mounting screws.