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 bandBandwidth:(within 2.0:1 SWR): 5MHzSWR:1.5:1 at 156.8 MHzImpedance:(ohms): 50Gain:6 dBMax Input (Watts):100DC Ground:YESTermination:SO - 239Height (feet):9.5Polarization:VerticalRadiation pattern:Omni-directional - cis2:mm5mnJlm -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)