DeltaLab NT100 Ninja Clip-On/Versa-Mount Chromatic Tuner Black Instant accurate tuning -- stealthy, invisible design when folded down behind headstock Versa-mount & clip-on bases included for use on a variety of instruments Hi-stick silicone backing is safe for most instruments* Auto-on / Auto-off feature for easy and instant tuning 360 swivel clip ensures viewing from any angle Visual metronome provides solid time-keeping Calibration range from 430-450Hz Battery strength indicator, so you know when it's time to replace batteries&lt;br The Ninja NT100 Versa-Mount Tuner from DeltaLab allows quick, accurate tuning while remaining invisible to your audience The versa-mount base attaches to the back of your headstock so the Ninja NT100 can fold flat when not in use Simply flip it open and the auto-on/auto-off feature engages, illuminating a super-bright fisheye LED readout With the included 360 swivel cup and clip-on base, you can use Ninja on other instruments as well  simply pop Ninja out from its versa-mount base and onto the clip-on base