The RodeLink Filmmaker Kit is a wireless lav mic transmitter and receiver. It uses 2.4ghz digital signals with encryption so you don’t need to worry about FCC licenses.
Both the transmitter and receiver pack are powered by two AA batteries so it’s always easy to have extra batteries on hand during a shoot. Both can also be powered via Micro USB.
The transmitter comes with a small wired lav mic in a little pouch.
Currently sells for $365 new. Asking $200 and I’ll pay shipping within the US.