LL1 is an exit door alarm with a flashing strobe designed to deter the use of the secured door by sounding a twin action alarm when opened by unauthorized Personnel. The alarm can be bypassed from inside or outside by the use of a key. (Requires standard Mortise cylinder not supplied.) this durable surface mount unit is easily installed and is tamper-supervised with two separate tamper switches. Its Test button verifies battery. Optional AC power supply available.