Does the Tripp Lite HDMI over Cat5/Cat6 Active Extender Kit support audio?

Yes, it supports stereo audio and HDCP.

What is the maximum extend distance for the Tripp Lite HDMI over Cat5/Cat6 Active Extender Kit?

The maximum extend distance is 125 feet.

double click image to zoom in

Tripp Lite HDMI over Cat5/Cat6 Active Extender Kit, Transmitter & Receiver, 1080p @ 60 Hz, USB Powered, Up to 125-ft. (B126-1A1-U)

Supports high-definition video resolutions up to 1080p (@ 60 Hz). Supports stereo audio and HDCP.
Works with all operating systems and HDMI sources
Built-in cable includes latching HDMI connector for a more secure connection
Built-in equalization control lets you adjust monitor image
Plug and play-no software, drivers or external power supply