I bought these speakers to use with my skiing helmet while working on the mountain with an FRS radio as a volunteer. The quality of construction is outstanding, and the audio is top-notch.
The only reason I gave four stars instead of five is that when I inquired about the connector, I was told it was 3.5 mm, and it probably is intended to be. It certainly isn't 1/4", but it wasn't 3.5 mm either. It would not fit in a 3.5 mm female connector, and when I measured the tip, it appeared to be closer to 4.5mm or so. (I didn't have calipers available, but eyeballed it against a Starrett rule.)
I used an edge stone to grind down the tip, and it fits into the 3.5 mm female connector and does work. I'll probably cut the connector off and replace it when I have time.