The KSN 1090A is an extended frequency range piezoelectric speaker designed to provide voice reproduction as well as higher frequencies. This speaker is lightweight with a thin profile, but robust enough to handle 50 W (EIA). The KSN 1090A is designed for applications that require a broad frequency range, small size, lightweight, nonmagnetic, rugged speaker.

If harsh environments are expected in your application, please check out the KSN 1103A speaker.

Link:http://www.bestgrouptechnologies.com/piezosource-ksn1090a-1103a.php