Audiosound or Game should have these wireless headsets. Most are Infrared, but u do get those who work with RadioFrequence(RF).
Be on the lookout when u go and buy though, cause some are mono others are stereo. Dunno why they make mono headsets, but for some reason they still sell them. Think it has something to do with it being cheaper to use hardware that only sends one audio signal(mono) vs two audio signals(stereo).
with Infrared u must be in range*usually around 10-12meters* and be in a direct line of site(around 35 - 45 degree's left or right from the recievers red lights), With radiofrequency the range is also around 10-12meters but goes in all directions, only to be obstructed by other obstructions like a wall etc..
These wireless puppies aren't cheap, the price that you'll pay will depend on wether u choose RF or ifrared, and also mono/stereo and also the different brandname.
If i can remember right, the last time i've seen the prices on wireless headsets in a Audiovision or game, they were around R350-R400 for Infrared stereo. The RF one was a little more. think R499. But then again this was almost 3-4months back. Its just a estimation. Also remember, it might be better to buy this next year. Since all the shops are in the Xmas spirit(aka hiking prices) *that xmas jingle u hear is just the sound of your money leaving yur pocket*
Anywho, thats my 2cents. Hope it helps
