Edson's 980-3-100 3 in Stainless Antenna Extension Designed to raise Loran or GPS Antennas above the Radar beam or to provide a mounting adapter for VHF antennas. Ideal of Mounting to Edson's Antenna Mounting Wings. Made of 1 in O.D. heavy duty stainless tubing with a 1 in -14 thread on top. 3 in dia. mounting base.