SOUND LEVEL METER The Extech 407750 Digital Sound Level Meter offers a big backlit display with an analog bargraph, PC interface and background sound absorber for superb accuracy. What differentiates this meter from others? The background noise absorber is optimal for noise measurements with high ambient noise levels, and the user can capture data to a PC using the optional Windows compatible 407752 software in the accessory tab. Scroll down to see more Extech 407750 sound level meter features and specifications. Specification:  Digital Display: 3-1/ 2 digit ( 1900 count) Autorange LCD Bargraph Display: 50dB display range ( 1dB resolution)  Measurement Range: 30 to 130dB ( 35 to 130dB for " C " weighting)  Resolution: 0.1dB Accuracy: ± 1.5dB@ 94dB for a 1KHz sine wave Microphone: Electret Condensor .24 " ( 6mm diam.) type Frequency Weighting: " A " and " C " type Time Response: Slow/ Fast Sampling Time: updates every 0.5 seconds Measurement Frequency Range: 31.5Hz to 8KHz Analog Output: AC: 0.70Vrms ( full scale) ; DC: 10mVDC/ dB Applicable Standards: IEC 651 Type 2, ANSI S1.4 Type 2 Power Supply: 9V battery, optional AC adapter Dimensions: 10 x 3.1 x 1.5 " ( 256 x 80 x 38mm)  Weight: 8.5oz. ( 240g)