Features: Large screen display with clear observation: 3.0-inch digital tube, capable of displaying even in direct sunlight. Wall mounted: with mounting holes/can be installed on the wall. Overs limit alarm prompt: The indicator light flashes during the alarm, accompanied by a buzzing alarm sound. External structure diagram: easy to understand and easy to get started with. Suitable for various occasion and widely used in bars, schools, hospitals, offices, etc. Can connect external speakers and support 3.5mm cable,Measuring ranges: 30 to 130dB, the product operation is very convenient, it can be used only by connecting the power supply (additional power supply needs 5V 1A) accuracy: ±1.5dB (reference sound pressure level, 94dB @ 1KHz), frequency response ranges: 31.5Hz ~8.5KHz Specifications: Material:ABS Accuracy: ±1.5dB (In Standard sound: 94dB@1KHz) Ranges of Measurement: 30 ~ 130dB Frequency Response Range: 31.5Hz ~ 8.5KHz Screen Size:3inch Package Includes: 1x Hanging Sound Level Meter note: Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item.