This Round LED Transom Light is approved for USCG 2 NM (Colreg 2 mile). Constructed of corrosion resistant stamped 304 stainless steel. Installs with two #8 RH fasteners (not included). All USCG approved navigation lights must be mounted properly to provide the correct visual alignment and allow unimpeded sight lines. Please refer to USCG regulations for 1 NM and 2 NM navigation lights for more information.