The Electro-Harmonix Single Expression Pedal is a versatile and affordable single-output expression pedal. It's designed to control devices with an EXP input, offering compatibility with various manufacturers' products. Features include a TRS polarity switch, reverse button, and range knob for fine-tuning the expression sweep. The pedal is built with advanced polymer construction, making it roadworthy and lightweight, and includes a six-foot TRS cable. It does not require power.