Hi Steve, I've been selling the universal WR set here and they are very popular. Built in batteries which charge off USB. Long press to turn on, short press to pair, very simple. The receiver unit also has a volume control which is nice, and on max volume you get a little bit of a boost on faint signals. Unlike bluetooth systems, there is no noticeable delay, and no degradation in sound quality. Drawback for some may be the estimated 6hr run time, but the great thing is you can just plug your headphone back into your detector and keep hunting.
The drop out issue of the original headphones was quickly sorted by a software update, and the original magnetic contact charging method was changed to a plug in USB. It is now a very good stable plug and play set-up, but most are waiting for the full ear cup headphones from Deteknix.