The M474HD antenna is a 7mm thick heavy duty fiberglass collinear covered with polyolefin for heavy duty use and weatherproof protection. The M474HD 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. The Look-alike Companion Antenna for 27MHz CB is The "DX125CDC". 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 works best on top of Raised Feed antenna.