LAMPHUS SoundAlert 100W 120-130 dB Volunteer Emergency Vehicle Warning Siren Speaker User Manual available for download under Product Information Details Constructed of heavy duty, rust resistant components. Integrated universal mounting bracket design allows for easy installation. 120 - 130dB Sound Compression Level; 100 Watt output, 8 Ohm Impedence. 400 Hz  4,000 Hz operational frequency spectra.; Unit comes with two electrical wires to be connected to a siren controller.