wire-free

[Chef Geoff]

LOL Bob I think I'll just stick with the longer lead on my Chefphones

David the reason there is no dedicated wifi headphones is purely because metal detecting is a micro hobby so the market simply isn't there, the more serious detectorists and gold prospectors wouldn't use wireless as it adds another potential weak point to their search and newbies and the occasional searcher probably couldn't warrant the outlay so suddenly your left with a very small market indeed.
The ones on the market  mentioned already are simply music headphones that have been sexed up to appear  as if they have been made for detecting but lack the sound isolation you really need