I think Garrett is just repackaging China product into their own custom design case. Cases are bigger to hold a larger battery to give you the longer run times.
From the specs I saw, appear to be the same specs as most wireless on the 2.4ghz frequency.
Think they see Deteknix making adapter modules for the Garretts as well as others so, making big profits, so they are getting in on it. To capture the market--longer run times.
Probably see Fisher and White's get in on it next.
Just seems like accessory prices are going up and up.....
I am curious to see if they are made in the US and not in China, its very well possible.