Specifications: The DT-805 noise meter/sound level meter has a wide dynamic range, as well as A/C sound level frequency weight and fast/slow time weight constant settings. The design meets the measurement requirements of engineering, health and industry, and can monitor the sound quality in various environments. Conform to IEC651 Type 2 and ANSI S1.4 Type 2 standards. DT-805 Features 1. Backlit LCD display 2. Maximum value/data holding function 3. Fast/slow time weighting 4. A/C sound level frequency weighting 5. Wide range 30 & 65374; 130dB 6.0.1dB resolution 7. High/low band measurement mode 8. Frequency response: 31.5HZ~8kHz 1. Open the battery cover and install a 9V battery; 2. Turn on the power supply and select the desired reaction time (F or S) and sound level frequency weighting (A or C); & 9312; If the sound source consists of a short burst or only needs to obtain the highest value of the sound, please adjust the response to the fast gear (F). For general sound measurement, please adjust to the slow gear (S). & 9313; A sound level frequency meter weight is applicable to measuring general noise level; The C sound level frequency meter weight is applicable to measuring the sound level of acoustic materials. 3. Select the level of high frequency band (Hi or low frequency band (Lo) to be measured; 4. Dig the instrument in your hand or fix it on a tripod, point the microphone at the sound source to be measured, and the sound level reading will be displayed on the display 5. When MAX mode is selected, the instrument will display the recorded maximum reading; 6. When the HOLD mode is selected, the instrument will display and keep recording the current reading; 7. Turn off the instrument after measurement and take out the battery when not in use. Main functions of DT-805 Applicable standards: IEC651 Type 2 and ANSI S1.4 Type 2 Range: 30~130dB Resolution: 0.1dB Accuracy: ± 1.5dB (at 94dB, 1 kHz reference condition) Frequency response: 31.5Hz~8kHz Sound level frequency weight: A and C Time weighting: Fast 125ms; Slow 1s Microphone: 1/2 inch polarized capacitive Calibration: at 1kHz sine wave, 94dB signal calibration Display: LCD with backlight Display digits: 3-1/2 Alarm function: "OVER" will be displayed when the input exceeds the range ”Automatic shutdown: after 15 minutes without any operation Power supply: a 9V battery (006P or IEC 6F22 or NEDA 1604) Battery life: about 50 hours (alkaline battery) Size: 210x55x32mm Weight: 230g