Style 399-1M VHF 6dBCollinear Phased 5/8-wave with two coaxial chokes to suppress cable radiationThe Style 399-1M is the same as the 399-1, but it has a special sleeve for mast mounting. A professional quality antenna in a compact package. This extra-duty antenna combines strength and performance for use where you really need the efficiency of a large antenna, but don&';t have room for one. Brass and copper elements Chrome-plated brass ferrule with standard 1"-14 thread Aluminum sleeve for mast mounting Suggested mount: 1-1/4" U-bolts are supplied. The 399-1M can be strapped to a larger mast using steel banding (not supplied) Two sections: Base 75"; Tip 39" UPS shippable Technical Specifications: Frequency: VHF Marine band Bandwidth: (within 2.0:1 SWR): 5MHz SWR: 1.5:1 at 156.8 MHz Impedance: (ohms): 50 Gain: 6 dB Max Input (Watts): 100 DC Ground: YES Termination: SO - 239 Height (feet): 9.5 Polarization: Vertical Radiation pattern: Omni-directional Specifications: Antenna Band: VHF Color: White Construction: Fiberglass Ferrule Type: Chrome Plated Length (Inches): 114" Box Dimensions: 5"H x 5"W x 88"L WT: 5.2 lbs UPC: 719441100032 Quick Guide (pdf)