Earvana Compensated Nut for Fender® Guitars 1-5/8" Curved Bottom. Earvana's patented technology is designed to improve the sound of your guitar. Reduces the difficulty of tuning the guitar such that the chords in the first 5 frets ring true for any open chords. Earvana has solved this problem by developing a nut that compensates for the errors that are inherent in 99% of all stringed instruments.