The HHSL402SD is a general purpose handheld instrument that measures the noise level of an environment or the sound level produced by a piece of machinery. Using an integrated 13 mm (0.5") condenser microphone, the meter can measure sound levels from 30 to 130 dB with a resolution of 0.1 dB and show the results on a front-panel liquid-crystal display. Several features and capabilities enhance the meter’s versatility.