SOUND LEVEL METER Features:  Meets IEC 651 Type I requirements and offers superior accuracy for critical measurements Large, easy-to-read LCD display Triple range measurement " A & C " frequency weighting AC output signal for use with dataloggers 1/ 2 " electret condenser microphone for high accuracy and longterm stability Internal 94dB calibration Data Hold, Max Hold and low battery indication Hard carrying case and batteries included Specifications:  Measuring Range: 30 to 130 dB ( A & C)  Resolution: 0.1 dB Accuracy: ± 1.0 dB Frequency: 31.5 Hz to 8 kHz Time Weighting: Fast/ Slow ( A & C)  Power Supply: 2 x 9V batteries Dimensions: 10.2 x 3.4 x 1.4 " ( 260 x 87 x 36mm)  Weight: 16 oz ( 450g)