Conforms to ANSI S1.40-1984 and IEC0942:2003 Class 2. Calibration Levels of 94dB and 114dB. Fits 1, 1/2 and 1/4 in. diameter microphones. Internal Battery Test. Output Frequency: 1000Hz +/- 2%. Output Sound - Pressure Levels: 114dB and 94dB re uPa under reference conditions. Reference Conditions: 1-Temperature: 68F (20C), 2-Relative Humidity: 65, 3-Atmospheric Pressure: 1013mbar, Temperature coefficient: +/- 0.02dB/C. Total Harmonic Distortion: <2 percent. Accuracy of Sound-Pressure Level: Under stated reference environment conditions +/- 0.5dB Power: 1 9V battery 006P or IEC 6F22 or NEDA 1604.