Metz 206 Manta-6 VHF Antenna. This is a slim, stainless steel 17-7 whip mounted to a nickel-plated brass post, then into a 1-1/2" diameter stainless steel coil.

Features:
UV-Resistant Cap
Soldered connections
Compression whip retainer
Comes with a stainless steel mounting bracket
AIS Compatible

Specs:
Length: 3' (34" Whip)
Cable supplied: No (separately sold)
Connector: SO-239 (not installed, but is supplied)
Band: Marine VHF band
Frequency Specs: 156 - 163 MHz
Gain: 3 dB
Max Output Power: 250 Watts
Wavelength: 1.2, shunt fed
Ground: internally grounded