I also use Samson wireless mic. If you are teaching cycling, use the backpack version as the sweat will eat up the wireless unit. If you get the wireless, with the transmitter in the headset, make sure you order the sweat guards that go over the little unit on the headset. Wipe down your headset after each use too.
I have used Samson for many years. You can contact KB Electronics in Madison Heights VA. One reason is they do all the repairs from Supreme Audio and others. They sell the units. I have dealt with them for over 10 years. 434-386-6262.