PLAY HARDER, FASTER, WITH MORE BENDS, FOR LONGER, AND STAY IN TUNE!One of the main reasons a guitar or bass goes out of tune is when the strings get stuck in the nut. Black TUSQ XL is impregnated with PTFE, the slipperiest substance in the world, allowing the strings to glide effortlessly over the nut slots while maintaining perfect tuning.With Black TUSQ XL, you’ll hear much greater tonal richness in every note you play. Designed with the same material as TUSQ, it delivers all the tonal benefits of TUSQ, bringing out hidden harmonics by efficiently transferring string vibrations to the guitar. Each piece of Black TUSQ XL is consistent and identical, providing harmonically rich tones without the problems associated with natural materials.