These Sonic Mini Compact Horns have no polarity, so the negative or positive wire can be attached to either side. Mounting bracket can be used as a wiring template. When installed, horns should point slightly downward to permit water drainage. At 108 decibels and a frequency (Hz) of 44020A, this horn meets US Coast Guard’s COLREGS and ABYC standard A-23 for use on vessels under 12m (39′). Constructed of impact and UV resistant ASA plastic. 12VDC.