Feature: 1. Fast/slow adjustable 2. Unit conversion.Fast/slow mode 3. Data retention.Auto Range 4. Fast response.A/C weighting 5. Max/Min value.Bluetooth communication Specification: Measure range: 30~130dB FAST Sampling rate FAST: 125ms SLOW Sampling rate SLOW: 1000ms Noise accuracy: 1.5dB Reference sound pressure standard: 94dB/1KHz Frequency response: 31.5Hz~8KHz Resolution ratio: 0.1dB Sensor type: 1/2 inch capacitive microphone Automatic shutdown: About 10 minutes Power supply: 3x1.5V AAA(not include battery) Working current: ~18mA Working temperature: 0-40C Working humidity: 80%RH Storage temperature: -20~60 Storage humidity: 80%RH Material: plastic colour: Black Package Contents: 1 x SL720B Noise Meter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.