Low profile design external sounder and strobe unit with 360˚ lens. 115dB Volume IP65 Environmental Protection Patented Safety Engineer Hold-off Mode Advanced Microprocessor Technology Screw, Lid and Wall Tamper Polycarbonate Construction Twin Piezo Sounders Selectable SAB/SCB Mode Strobe Tube Saver Twin Alternating LEDs PD6662:2017 Grade 3 Class IV