Engineered Thermoplastic Slot Mounted nuts for Fender® Style guitars Are injection molded replacement nuts featuring resonant Massive™ Nut Technology, PEEK 30% GF base parts and Low Friction PEEK 20% PTFE saddle parts. They are available in a variety of sizes, colors, fretboard radius and string spacing. Please check your instrument or ask your luthier to make sure you order the right size.