Check the listing for details. Electro-Harmonix EHX Mod Rex Polyrhythmic Modulator Guitar Effects Pedal w/ MIDI. Condition: New. Listed at 283.80 USD. Get ready to add some serious modulation to your guitar sound with the Electro-Harmonix EHX Mod Rex Polyrhythmic Modulator Pedal. Designed for guitarists who want to experiment with new sounds and textures, this pedal features advanced polyrhythmic capabilities that allow you to create complex, layered rhythms that will take your playing to the next level. With its intuitive controls and versatile range of modulation effects, including filter, flanger, chorus, and phaser, the EHX Mod Rex pedal is the perfect choice for musicians looking to add some unique flavor to their sound. Whether you're a seasoned pro or just starting out, this powerful modulation pedal is sure to provide hours of creative inspiration.