SPECIFICATIONS MODEL 321 Level Range Lo = 32-80 dB Med = 50-100 dB Hi = 80-130 dB Frequency Range 31.5 Hz to 8 kHz Dynamic Range 50 dB (100 dB in Autorange Mode) Accuracy ± 1.5 dB (ref 94 dB @ 1 kHz) Display 4 digit LCD with Bargraph Frequency Weighting A, C Time Weighting Fast, Slow Microphone 1/2" Electret condenser Auxiliary Outputs AC/DC outputs Power 9V Battery Battery Life 50 hours (with alkaline battery) 50 hours (with alkaline battery) -23 to 104 °F (0°C to 40 °C) <90%RH Dimensions 10.8 x 2.5 x 1.2" (274 x 63 x 30 mm) Weight approx. 5.78 oz (180 g) RS-232 Interface Cable and Windows Software Optional