Triax is a cable used primarily in analog video camera applications. It contains a coax, inner jacket, braid, and overall jacket. The coax is used to transmit the video signal. The two braids are used to send power and multiplex various other signals from the CCU to the camera.
Belden manufactures Triax cable. Various triax cables are available in RG-59/U RG-6/U and RG-11/U 75 ohm constructions.