The top choice for charter boat captains & experienced sport fishing enthusiasts. This long-distance VHF antenna is rigid enough to stay erect in rough seas, yet exceptionally lightweight. The 4018-M has an aluminum sleeve for attaching to a mast. It is used primarily for land-based stations & on commercial vesselsPhased 1/2-wave elements in a collinear array with a coaxial choking sleeve to suppress cable radiationMast mount - U-bolts suppliedSO-239 connector at base of antenna2 Sections: Base 162"; Tip 66"Land-based stations & commercial vessels; for medium to large fishing & commercial vessels & similar types of vessels applicationColor: WhiteInput Impedance: 50 OhmsPower Rating: 50 WattsSWR: 1.5:1 at 156.8MHzBandwidth: 3MHz within 2:1 VSWR