Korg's Pitchblack Portable Polyphonic guitar tuner is a nice width or sideways oriented tuner. You can keep it "always on" for on the fly tuning within a song. Can be used as a mute switch and has a vivid and bright led display. Will fit in nice on that long skinny space on your pedalboard you don't know what to do with. Also puts in a light show while you are playing if you keep it on.