The S521 features a mahogany body bolted to a maple Wizard III neck with a 24-fret rosewood fingerboard with offset dot position markers. Components include dual Ibanez Quantum humbucking pickups, a fixed bridge, a plastic nut and Ibanez tuners. For 2018 the rosewood fretboard was replaced by jatoba. For 2019 the mahogany body was replaced with meranti. For 2020 the bridge was changed to the F106. For 2021 the fretboard was reverted to rosewood.