18″ Antenna Extender – White Constructed of high-quality reinforced fiberglass and finished to match Digital Antennas award-winning antennas, our antenna extenders are used to increase the height of an antenna to improve effective range or to place an antenna above on-board obstructions that may interfere with proper radiation. All extenders mount standard 1″14 threaded mounts. Use a center brace when the combined length of your antenna and all extensions is more than 8′ Features: Heavy duty fiberglass Stainless steel ferrules 1″14 threaded top and base High gloss urethane finish