Sound Level Calibrator, Output Sound Pressure 114 dB, Frequency Accuracy +/-4 Percent, Frequency Source 1,000 Hz, Distortion +/-0.5 dB, Compatible with Brand Universal, Compatible with Manufacturer Model Number SM-10, SM-20A, Output Sound Accuracy +/- 0.5 dB, Battery Chemistry Alkaline, Batteries Included Yes, Battery Size 9V, Battery Voltage 9V, Minimum Operating Temperature 32 Degrees F, Maximum Operating Temperature 104 Degrees F, Includes 1/2 in Adapter