AIS Antennas4' Length, 4.5dB GainIn conjunction with the USCG Automatic Identification System (AIS) requirements for commercial vessels, Digital Antenna created a series of 4 AIS antennas that meet the exacting AIS frequency requirements. Designed with a low 1.5:1.0 SWR ratio from 159-162 MHz, Digital Antennas 4.5 dB gain AIS antennas offer unsurpassed durability and performance compatible with all AIS transponders.Customers and installers love the 500 GOLD Series easy installation connector system. The gold factory-attached mini-UHF female connector with PL-259 (UHF) adapter makes connecting to the AIS transponder easy, eliminating the need to solder connectors.All of our antennas are made in the USA, assembled, tested and tuned by hand for maximum performance, quality and durability.All 4' AIS Antennas Feature:Powerful brass radiators Soldered connections Power directing ferrite choke bead High gloss urethane finish 316 stainless steel ferrule 4.5dB gain 500 GOLD SeriesMount: Standard 114 threaded base Connector: Gold factory-attached mini-UHF female with mini-UHF male to UHF male (PL259) adapter Cable: Includes 25 of our low-loss, tinned braid, foil shielded, UV stable RG-8X marine cable