The Korg DTR-1000 rack mount tuner has essential features for the pro guitarist.

A must-have item for professional musicians for both studio and stage use, packed with essential features for pro guitar performance.

Chromatic tuner that automatically detects the note name and accurate pitch
Seven semi-tone flat tuning support
Two types of display: cents or strobe
Adjustable calibration of 438--455 Hz. (Manual/Auto)

Now Superseded by the Korg DTR-2000, but old available and used tuners are wideley available.