Vintage Zen-on Justina quartz guitar tuner, Model 395. Produced in the 1980s. Portable, battery-powered (9V) guitar tuner that uses an analog needle display to indicate pitch.
The tuner can be set to different reference pitches (A4) at 430, 440, or 450 Hz.
The "Cent" display indicates how sharp or flat the note is from the target pitch, with a range of -50 to +50 cents.
It features both an input jack for direct guitar connection and an output jack for passing the signal through to an amplifier.
A switch allows users to select between notes E, A, D, G, B, and E for standard guitar tuning. Tested and Works.