http://www.aikencolon.com/extech-hd-600-data-logging-sound-level-meter.html
The Extech HD600 HD 600 Sound Level and Decibel / Noise meter that can store up to 20,000 records with real date and time stamp. The HD600 has a 30 to 130dB range with 1.4dB accuracy with data logging capability up to 20,000 records at speed from 1/sec to 1/59sec .
