3-1/8″ 50 Ohm 4-Port Socket Swivel Flanged E.I.A.These Coaxial Dynamics Line Sections, with appropriate meter (portable or panel mount) and plug-in elements, form a complete system to measure power in 50-Ohm 3-1/8″ transmission lines.Several different models are available in either single socket or dual socket with Flanged, Unflanged Flush, or Unflanged Recessed connections. Dual socket line sections allow both forward and reflected power measurements using only one line section and a meter with a FWD/RFL switch, or a panel mount configuration with 2 meters.Your confidence in the quality and dependability of these Line Sections is assured with the Coaxial Dynamics Two Year Limited Warranty. Silver Plated For High Conductivity Low Insertion VSWR – 1.05:1 Max Uses Standard Gold Plated Plug-In Elements Rugged and Reliable Two Year Limited Warranty