Features: Type:Decibel Meter Sampling Rate: 2 times / second Dimensions:256 x 70 x 35mm Measuring Level: 30 ~ 130 dB(A) Accuracy: ±1.5 dB Frequency Response: 31.5 Hz ~ 8.5 kHz Description: Plotted graph and recorded data are printable High accuracy up to ±1.5 dB With 2 equivalent weighted sound pressure levels A and C Fast/Slow time weighting selection Automatic power off when idle for 10 minutes Tested compatible with Microsoft Windows XP / Vista / 7 (32 bit and 64 bits)/8/10 Specifications: LCD display: 4 digits Resolution: 0.1 dB LCD size: 2.2 inch(55mm) Display: 0.5 secretary Sound Level: Level 1: 30 ~ 80 dB Level 2: 50 ~ 100 dB Level 3: 60 ~ 110 dB Level 4: 80 ~ 130 dB Level 5: 30 ~ 130 dB Dynamic Range: 50 dB / 100 dB Frequency Weighting Characteristic: A / C Analog Bar Graph: 1 dB / 1 bar graph PWM Signal Output: duty cycle = 0.01 x dB value x 100% / 3.3 Dynamic Characteristic (Time weighting): FAST(high speed) / SLOW(low speed) Calendar Accuracy: ±30 seconds / day Microphone: 0.5 inch polarization capacitance microphone Power Supply: 4 x 1.5V AA battery (not include)or USB Cable Power Life: about 20 hours continuous use (alkaline battery) Operating Temperature: 0 ~ 40 °C (32 ~ 104 °F) Operating Humidity: ≤80 % R.H. Include: 1 x Decibel Meter 1 x English Manual 1 x CD