Product Description This 1kHz, 94dB professional sound calibrator for 0.5" or 1.0" microphones calibrates and verifies sound level meter operation. Battery test position with battery status LED indicates if battery is good. Durable die-cast aluminum housing generates a 1kHz sine wave at 94dB to an accuracy of 5% (frequency) and 0.5dB (94dB). Meets IEC standard 60942 1997-11. Complete with two 9V batteries, carrying case, and screwdriver. From the Manufacturer 1kHz 94dB professional sound calibrator for 0.5" or 1.0" microphones calibrates and verifies sound level meter operation. Battery test position with battery status LED indicates if battery is good. Durable die-cast aluminum housing generates a 1kHz sine wave at 94dB to an accuracy of 5% (frequency) and 0.5dB (94dB). Meets IEC standard 60942 1997-11and comes complete with two 9V batteries, carrying case, and screwdriver. Noncontact rpm measurements to 99,999rpm with integral light beam Make noncontact rpm measurements of rotating objects Use reflective tape on object to be measured and point the integral light beam Ideal measurement range up to 6Inch 152mm distance Readings updated every second