I have used the Dewalt for years, I upgraded to the Bosch that has a speaker in each corner, and a sub on the bottom, and the batteries are even cheaper.......
Grey area. Any radio the can pick up AM/FM technically has a transistor. I use my portacable radio. Indestructible, and last the whole shift if I keep it half way.
When I was on package car I had a sirius boombox, plugged it into an inverter which clipped to the truck's battery. I just built this for the jockey wagon.