The 2 point acoustical calibrator will calibrate any digital sound meter with a 1" or 1/2" microphone. It conforms to ANSI S1.4-1984 and IEC 60942-2003 Class 2 standards for acoustical calibrators. Simply place the calibrator on to the digital sound meter's microphone, turn on the calibrator and adjust the meter's reading to either 94 or 114 dB. It operates at a frequency of 1KH +/-2% and with an accuracy of +/- 0.5 dB. It features a built in battery check, and is easily portable for field use and includes a carrying case, adapters for 1/2" or 1" microphones, instructions and a 9 volt battery. Weight: 6 ounces, Dim 4.5" x 2.5" x 1.5".