Miniature Piezo Alarms 103 dB @ 2 feet The original high output miniature piezo alarm, designed and made in the USA Floyd Bell's M-80 Series, first sold in 1989 and redesigned in 1999, is a solid-state, environmentally secure miniature piezoelectric alarm that is typically 20 dB louder and 1000 Hz lower in frequency than alarms of comparable size. Approximately 1" in diameter × 0.875" in height, it packs an explosive sound output of 103 dB @ 2 feet. The M-80 PC mount and PM-80 panel mount piezoelectric alarms feature an expanded voltage range of 5-15 VDC. The M-100 PC mount has an expanded voltage range as low as 3-6 VDC.