3 1/8" 50 ohm 20' optimized expansion line assembly, flanged: Includes "O" ring, hardware. Used on TV CH 7, 8, 11, 12, 14, 15, 18, 19, 22, 23, 27, 31, 35, 39, 43, 44, 47, 48, 51, 52, 55, 56, 60, 64 and 68. 55.5lbs.