Features of Decibel Sound Level Meter Lutron SL4030: This dB sound meter features a large, easy-to-read LCD display. “A” frequency weighting provides accurate measurements and complies with IEC 61672 Class 2 standards. This decibel meter includes a fast time-weighting mode for responsive noise analysis. Built-in adjustable VR allows for convenient on-site calibration. A condenser microphone ensures high accuracy and long-term measurement stability. This hold function lets users freeze the current reading on the display. Over-range and under-range conditions trigger a clear warning indicator. This LCD offers low power consumption and remains visible even in bright lighting. Constructed with durable, long-lasting components and a lightweight ABS housing. Compact and lightweight, allowing comfortable one-hand operation. A low-battery indicator alerts users when power is running low. High-quality performance at an economical cost.