Affordable Back up alarm 12-24 Vcc, 82- 102 dBA

The Smart Alarm® from ECCO was the world's first self-adjusting back-up alarm, constantly measuring ambient noise and adjusting their sound level, creating a volume that is safe without being annoying or contributing to noise pollution. 

Smart Alarms® eliminate the need for constant manual adjustment and help prevent intentional alarm disconnection. Compact size and universal mounting bracket maximize location options, self-grounding with stud terminal connections, sealed in epoxy for protection against dust, moisture, and vibration.