One Control MKII with BJF Buffer, pedal tuner for electric instruments, chromatic, high quality BJF buffer or true bypass (switchable), easy-to-read display, tuning range E0 (20.60 Hz) - C8 (4186 Hz), reference frequency adjustable: 436 - 445 Hz (in 1 Hz steps), accuracy: +/- 0.5 cent, switch for BJF Buffer on / off, Calibration button for selecting the reference frequency, Bypass footswitch, metal housing, current draw max. 40 mA, power supply via optional 9V DC power supply (not included), 2.1 mm x 5.5 mm barrel plug, polarity (-) center, dimensions (W x L x H) 44 x 94 x 47 mm / 1.73 x 3.7 x 1.85 , weight: 234 g / 0.52 lbs