The new L-Series from System Sensor include: Accessories, Chimes, Chime Strobes, E CS and MNS, Horns, Horn Strobes, Speakers, Speaker Strobes, and Strobes. The SpectrAlert®? Advance low frequency sounder strobes meet the new NFPA 72® 2010/2013 low frequency (520 Hz) requirements effective January 1, 2014 for sleeping spaces. They include a universal mounting plate with a plug-in design, two sound patterns for the sounder, 24-volt operation, and are compatible with the System Sensor synchronization protocol.?