Calibrates and verifies Sound Level Meter operation 1kHz sine wave at 94dB/114dB is generated to an accuracy of 5% (frequency) and and "0.5dB (94dB)/"1.0dB (114dB) LED indicator lights up when power is on Level position to select 94dB or 114dB For use on Sound Level Meters with 0.5 Inch or 1.0 Inch microphones Durable die-cast, aluminum housing Specifications Power consumption Approx. 10mA DC Distortion % Total Harmonic Distortion (THD) Accuracy "5% "0.5dB (94dB), "1dB (114dB) Noise Level 94dB/114dB Weight 0.75 lbs. (340g) Frequency 1000 Hz Operating temperature 32 to 122"F (0 to 50"C) Power supply Two Heavy duty, alkaline 9V Battery Dimensions 2.2 diameter x 5.6in long (50 x 127mm)