13 In 1 Multifunctional: This decibel meter is 3 in 1 multifunctional with noise meter, thermometer, and hygrometer, providing convenience for your work and life. 2High Accuracy: This decibel meter uses smart air semiconductor sensors to test decibel temperature and humidity values, which is more sensitive, accurate and stable. 3Wide 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. 4Built 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. 5Excellent 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. 1 x 3 In 1 Decibel Meter 1 x Manual 1 x USB Cable 1 x Installation Sticker 2 x Screws 2 x Expansion Tube