We also recommend the new Sewell v-Link VGA over Single Cat5 which features the exact same specs and quality for less.
When it comes to extending a VGA and Audio signal, the most efficient way is over Cat5 cable. The Gefen VGA and Audio Extender can send a 1080p, 1920 x 1200 video signal as well as an analog L+R Audio signal (3.5mm) up to 330 feet or 100 meters using just a single Cat5 cable.
Perfect for digital signage applications, this package includes one sender unit and one receiver unit. The video in on the sender unit is VGA HD-15 and sits next to your video source with VGA-out such as a computer. Then using any Cat5 cable, (not included), run your signal to where you need it, such as a board room projector or display, trade show booth TV, or any other application you could use this with. The receiver unit sits next to your video display and returns the signal from Cat5 to VGA. Using 3.5 mm audio jacks, these units act the same way for analog audio. Both units are required to be plugged into the provided power supplies.
The Audio feed supports bi-directional transmission for speaker and mic support.