Disconnecting the vehicle battery is one of the standard ways of silencing a car alarm. A battery back-up siren defeats that — it holds its own power source, so it keeps sounding after the vehicle battery is cut.
It's noticeably smaller than a conventional siren, which matters more than it sounds. Modern engine bays are crowded, and finding a concealed mounting point for a full-size siren is often the hardest part of the install.
Supplied as standard with the M80II and M80GII, and suits any alarm with a resistive ground positive trigger — including the M33, M80S, M80G, MAP80S and MAP80G.
Two battery isolating keys are supplied so the siren can be isolated for vehicle battery servicing without disabling the alarm itself.
