Extech SL400 Personal Noise Dosimeter Real Time Datalogger is a personal portable datalogging device for measuring noise levels in order to comply with safety requirements set forth by OSHA, MSHA, DOD, ACGIH, and ISO standards. The Extech SL400 can track total noise exposure over an 8-hour period for OSHA and IEC Noise accumulation surveys, is compactly deisgned, and features a USB interface to analyze readings on a PC. Extech SL400 also has adjustable Criterion Level, Exchange Rate, and Threshold, as well as the option to be used as a stand-alone sound level meter.