All you need is an adapter/dongle bluetooth transmitter with the correct male plug to go into the GPX battery headphone jack. There are only a couple that I found that have the 1/4 size....most just come with the 3.5 mm.
It does work with the Nox's low latency wireless headphones. It will work with any Bluetooth headphones or ear buds....but you need to make sure they are low latency. I am using my Nox headphones with the wireless adapter. It is so small that it slides right into the battery pack harness compartment.
My only complaints are....it is picking up some static from somewhere. I can hear it thru the headphones. And the Nox headphones do not have great sound quality to start with. They are just $40 headphones...Miccus SR71s. You can really tell the difference if you are used to using a good pair of wired headphones with the GPX. I am thinking about buying a different set of low latency wireless phones...going with a higher end model, and seeing if it clears up the static and makes the tone clarity better. But yes...the GPX can be made wireless on the headphone side of it.