Antenna ExtendersConstructed 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&';All Antenna Extenders Feature: Heavy duty fiberglass Stainless steel ferrules 1"14 threaded top and base High gloss urethane finish 528-EWDimensions: 4&'; - 1" O.D.This product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns. Specifications: Type: Extension Box Dimensions: 3"H x 3"W x 53"L WT: 3 lbs UPC: 839494001770 Quick Guide (pdf)