Thermax/Sonic - RG142 Teflon Cable The Thermax/Sonic RGS142 Teflon plenum-rated coaxial cable (brown) is NEC CMP rated. This 50 Ohm coax cable utilizes dual silver shields for 98 percent coverage. The 3/16 inch transmission line passes the VW1 vertical wire test and is Mil Spec MIL-C-17G rated. This RG142 coaxial cable has a solid center conductor and a brown-tinted FEP jacket with extruded PTFE double shield as insulation. The Thermax/Sonic Teflon plenum-rated coaxial cable is available in bulk (may not be available in long continuous runs) and is priced per foot.