I am interested in installing a stereo in my recently refurbished hot tub. I was thinking of an undershell system, How well do these work? Where can I get the stereo and speakers from? What is the best way to run power to the stereo

I did a little surfing and the head unit is pretty straight forward. For example Coleman uses a JBL MR-17. Its a marine radio. I don't know if there is a special case for the head unit. I had no luck finding someone who lists the pop up speakers.
I would think it would make more sense to use some sort of wireless stereo based off of your home stereo.
There is a 900mhz (like a phone signal) single speaker at best buy for $100.
Water proof speakers are pretty common.
There is also a wifi transmitter so you could play mp3 files from your computer. I guess they have to be seperatly powered.
Mixing a stereo and a hot tub just sounds like a bad idea. I would think it would be a compromise to mount then in the tub. You also have to think about how your cover seal will be affected.
John