Mooer Slow Engine Volume Swell Bowed Effect Pedal w/ Power Supply Includes a Power Supply! Input : 1/ 4"monaur al jack (impedance: 470k Ohms ) Output : 1/ 4"monaural jack (impedance: 100 Ohms) Power Requirements: AC adapter 9V DC (centerminus plug) Dimensions: 93. 5mm (D) 42mm (W) 52mm (H)