This Tusq top nut from Graph Tech for some PRS / Ibanez guitars is made from a plastic that looks and feels like Ivory.
This man made material is made to be free of inconsistencies and impurities which can be found in natural materials.
This means that the vibrations from the strings are passed to the body of the guitar, enhancing tones, sustain and increasing the rich harmonics which results in crisp highs and powerful lows, bringing extra life to your guitar.
Tusq nuts are oversized and have extra length and height so that you can shape them to your requirements by simply sanding it with a 200 grit sandpaper.
Measure the E to e spacing, width and length of your current top nut and find the closest match that is slightly larger than your current top nut.
E to E – 35.22mm / 1.387"