The 42AG Multifunction Sound Calibrator from G.R.A.S. Sound & Vibration (Twinsburg, OH) was designed for fast verification of microphones and sound-level meters in the field. Developed as an improved replacement for the company’s 42AB Sound Calibrator, the 42AG can calibrate at two frequencies, 250 Hz or 1 kHz and at two levels, 94 dB or 114 dB. According to the company, this makes the 42AG suited for calibration of sound-level meters that normally are calibrated at 1 kH, as well as for calibration of microphones that normally are calibrated at 250 Hz. In addition, the 42AG can calibrate at two different sound-pressure levels. The 42AG Multifunction Sound Calibrator is portable, battery-powered and designed specifically for in-the-field operation.