3 IN1 DECIBEL METERFDM01 is not only a decibel meter, but also a temeprature meter and humidity meter. ACCURATE MEASUREMENT]The measuring range of the sound level meter is 30dB to 130dB . Highly accurate with 1.5 dB. Realtime monitoring gives you accurate data on noise in the area. AUDIBLE AND VISUAL ALARMSSetting highlow alarm values, if the measured value higher than it,Red color alarm back light will light up to alert you it is over the highlow alarm value. BUILT IN RECHARGEABLE BATTERY With 600mAH builtin rechargeable battery, you need to buy extra 3A battery to power your deceibel meter. It is more convenient to use. COLOR SCREEN AND BLACKLIGHT Color screen makes data easy to read. With the backlight feature,it is appropriate for gathering the sound data at night. Backlight auto power off function is provided. With power saving and highreliability circuit design,welldesign highefficiency power supply circuit makes the batteries more durable COMPACT AND STURDY DESIGN Composite material injection molding process is adopted for casing with antidrop structure design. It is not only extremely wearresisting, but also elegant, Its a mini handheld portable sound level meter.