GRAS Sound & Vibration
GRAS 42AA Pistonphone
GRAS 42AA Pistonphone
A precision sound source for acoustic calibration, providing a stable reference level for calibrating measurement microphones, sound level meters, and related equipment.

GRAS Sound & Vibration
A precision sound source for acoustic calibration, providing a stable reference level for calibrating measurement microphones, sound level meters, and related equipment.
