Extech SL10  

Extech SL10: Pocket Series Sound Meter

Compact, One-Button Operation Sound Level Meter

The SL10 convenient pocket-sized sound meter is easy to use and easy to stow. Keep one handy for whenever you need to take a quick sound level measurement. Measures sound level from 40 to 130dB with a Frequency Weighting for human hearing and fast response time of 125ms. Complete with 9V battery.