Electro Harmonix EHX-2020-2.0 Pedal Tuner.
The EHX-2020-2.0 Pedal Tuner is super compact and takes up minimal space on your crowded pedalboard. Switchable True Bypass / Buffered Bypass for easy integration into any rig, while its +/- 1 cent tuning range and high visibility display provides an accurate, convenient solution to all your tuning needs.

Quick specs:
• Chromatic pedal tuner with a tuning range of B0 to B7
• Switchable True Bypass / Buffered Bypass for easy integration into any rig.
• The pedal’s output is muted when the tuner is engaged which makes it ideal for live performance
• Accuracy: +/- 1cent
• Calibration: 436-445Hz (1 Hz steps)
• Three flat tuning modes
• Power adapter included