Bluetooth function is added for data transfer and analysis on the mobile app, which can be downloaded in the App Store. Plug and play, there is no need to re-calibrate before use, This Bluetooth noise meter with a wide measuring range: 30–130dBA. Accuracy: up to ±1.5dB; Resolution: 0.1dBA; Measures frequency in dBA - relative to the sound level perceived by the human ear. Perfect for measuring noise levels in loud areas to give you an accurate reading. Data hold function, maximum and minimum value measurement. Fast and slow sampling rate for choice: 125ms or 1 second. LCD screen display with backlight, convenient to use at night. </ul> UT353BT Bluetooth Mini LCD Digital Sound Level Meter 30-130dB UT353BT is a portable digital audio meter that can convert ambient noise into electrical signal to measure and process data. It has a compact and easy-to-use design with a friendly user interface. Bluetooth function is added for data transfer and analysis on the mobile app, which can be downloaded from the App Store. <b>Specifications:</b> Model: ut353bt Size: approx. 15.5*5.2*3 cm/15.5 x 5.1 x 3 cm Weight: 167 g Bluetooth: 4.0 Storage: 1 g and above Battery Type: 1.5 V 3 * AAA Battery (not included) Noise (A-weighted): 30 to 130 dB, 0.1 dB, ± 1.5 dB. Frequency Response: 31.5 Hz to 8 kHz. Sampling Rate: Fast: 8/s. Slow: 1/s. Overload Indication: OL/ONU. Max/Min: Yes. Data Hold: Yes. LCD backlight: Yes. Auto power off: 5 minutes. Low battery indication: 3.0 ~ 3.5 V. USB interface: Yes. Full battery life: > 12 hours with Bluetooth function. Storage environment: -20 to 60 degrees Celsius (= <80% RH). Color: Gray and red. <b>Package Contents:</b> 1 x Sound Level Meter (battery not included) 3 x 1.5 V AAA batteries (included)