Deltabell Plus External Sounder Module The Deltabell PLUS provides light to cover to provide around the clock visual deterrent A number of engineer friendly features; the unique levelling mechanism and modular components now make simple sounder installation a reality for you. 109dBa at 1M 3 Way tamper action Universal triggering inputs Supplied with rechargeable battery Low voltage / power consumption Engineer hold off Remote engineer hold off 3 Way tamper action - Activation from front, back, and power supply cut off ensures protection from sabotage attempts. In this situation, the siren will activate independently of the control panel. Universal triggering inputs - Can be connected to any output on a manufacturers control panel, positive applied, negative applied, positive removed, negative applied. Supplied with battery - Complete with a backup battery so that even in the event of an intruder sabotage, the bell box will still operate and protect the p