Revolutionary Miniature Piezo Alarms 103 dB @ 2 feet Floyd Bell's stylish new Turbo Series piezoelectric alarms are twice as loud and half the size of industry counterparts. Size is approx. 1" dia. × 1" high. Panel and PC mounting available. Frequency: 2900 ±250 Hz. Our new, included rotary volume control has twice the attenuation of industry counterparts. These powerful, rugged alarms have the highest output, and are the most water and vibration resistant sound devices of their kind in the world. Best of all, they are UL recognized and 100% made in the U.S.A. Each alarm is tested three times before shipment. Standard mounting hole is 11/16" or will fit 11/8" with the included thick gasket. Free Volume Control and NEMA Type 4X Gasket Included