Feature: 1. 3 In 1 Multifunctional: This decibel meter is 3 in 1 multifunctional with noise meter, thermometer, and hygrometer, providing convenience for your work and life. 2. High Accuracy: This decibel meter uses smart air semiconductor sensors to test decibel temperature and humidity values, which is more sensitive, accurate and stable. 3. Wide Application: This decibel meter has a wide range of applications and can be used in classrooms, studios, major transportation arteries, factories, construction sites, homes, offices and more. 4. Built In 2000mAh Lithium Battery: This decibel meter has a built in 2000mAh lithium battery and comes with a 10 foot USB charging cable, so you can put it anywhere you want and charge it on the go. 5. Excellent ABS Material: This decibel meter is made of excellent ABS material, which is sturdy and wear resistant, not easy to be damaged, and has a long service life. Specification: Item Type: 3 In 1 Decibel Meter Material: ABS Display: LED Display Air Pressure: 12.5PSI-15.4PSI Sampling Time: 1.5 Seconds Temperature Range: 14℉-140℉ Storage Temperature: 14℉-140℉ Relative Humidity: 20%-85% Humidity Range: 20%-85% Charging: 1000 mAh 5V Battery: Rechargeable Lithium Battery 2000mAh x 1 ( Shipped With Built In Battery ) Size: Approx. 10.6 x 3.5 x 1.4in/26.92 x 8.89 x 3.56cm Concentration Unit Decibel: dB Measurement Range: 30-130dB Accuracy: ±1.5dB Frequency Range: 50Hz-8.5kHz Frequency Weighting: A Resolution: 0.1dB. Package List: 1 x 3 In 1 Decibel Meter1 x Manual1 x USB Cable1 x Installation Sticker2 x Screws2 x Expansion Tube