Electro-Harmonix Mod Rex Polyrhythmic Modulator Guitar Pedal (Used)Condition: Used Like New Condition Details: Fully functional with no visible wear; original packaging included (may show light handling). The Electro Harmonix Mod Rex Polyrhythmic Modulator Guitar Pedal is a powerful modulation tool designed for multiple instruments to stretch your musical boundaries. The EHX Mod Rex is a kinetic tour de force that lets you weave compelling, shifting, musical tapestries. Whether you are a guitarist, synthesist, or