The M476 antenna is a high gain 7mm thick heavy duty fiberglass collinear covered with polyolefin for heavy duty use and weatherproof protection. The M476 works best when mounted onto a bracket that is as close to the surface of the ground plane as possible such as the BMB mount. Do NOT use a spring base or Z bracket mounts with this antenna, use the BMB Mount for the best performance and SWR! Recommended Accessories - UL12C with BMB or MAG12C Warning - DO NOT use this antenna on Raised Feed such as the RF470 range