Our plenum HDMI are made of a low smoke CMP jacket and a teflon inner insulator The cables have passed a stringent burn test and are ready to be installed in drop ceilings or plenum air spaces such as non-ducted HVAC air returns. Features: 340 MHz (over 10.2 Gbits/s) Supports all digital audio formats 24k Gold plated connectors Shielded to block EMI and RFI 24 AWG UL Listed