The Boss TU3S compact tuner pedal is small enough to fit on any pedal board, but with a nice large display easy enough to be seen in any enviroment.  It has all th eaccuracy and features from the regular TU3, but minus the on/off switch, so its always on and ready to go.

Respected TU-3 tuning performance in a more compact size

21-segment LED meter with brightness control

High Brightness mode enhances meter visibility outdoors

Accu-Pitch Sign function provides visual verification when tuning is complete

Chromatic and Guitar/Bass modes, with support for 7-string guitars and 6-string basses

Guitar Flat mode supports “drop” tunings up to six semitones below standard pitch

Powered by optional PSA-series adapter; DC Out jack for powering up to seven BOSS compact effect pedals via an optional PCS-20A daisy-chain cable

BOSS five-year warranty