Low Profile Combination Bow Light is for replacement of existing lighting (not for new construction). Constructed of die cast chrome zinc. Lens can be reversed for under mounting. Installs with two #10 FH fasteners (not included). Recommended for fresh water use. These navigation lights do not meet the USCG 33 CFR 183.810/ABYC standard A-16 from 2016, but do meet the USCG 33 CFR/ABYC A-16 from 1997.