Compact expression pedal with Passive Voltage Control/ Expression operation. No battery or power adapter needed. Smooth consistent taper to ensure accurate control of various parameters. Device can be used to hook up to any device with votlage control or expression capability via TRS stereo Jack. Morley M2 Mini Expression is suitable for use with any device that has voltage control or expression pedal feature. Pedal is set in a Cold-rolled steel housing for maximum durability. Color: Black.