TU-80
http://www.roland.com/products/en/TU-80/
The BOSS TU-80 brings super-accurate LCD tuning to a very affordable price, while adding unique features like a built-in metronome and Accu-Pitch. The pocket-sized TU-80 runs on batteries and can tune almost any instrument, thanks to a chromatic tuning mode. It even tunes 7-string guitars and 6-string basses—putting the TU-80 in a class all its own.
TU-15
http://www.roland.com/products/en/TU-15/
The BOSS TU-15 Chromatic Tuner gives guitarists the most accurate tuning possible—bolstered by new Accu-Pitch and Octave Adjust functions—plus popular Drop D, open and flat tunings. A backlit needle and LCD make tuning easy, while improved high-impedance inputs let you connect between an amp and guitar without signal loss.
TU-12 / TU-12H
http://www.roland.com/products/en/TU-12/
The worldwide standard used by top musicians everywhere, thanks to extremely accurate, easy-to-use tuning.
TU-2
Legendary BOSS tuning in a convenient, easy-to-use compact pedal design. A 7-segment LED and 11-point Stream Meter ensure accurate tuning, even in low-light settings or under bright stage lights.