The Turtle Shell Wireless Boom Box is water resistant and built to keep rocking even in the rain or the surf. The speaker costs about $150 from Outdoor Technology.
The case has a screw mount on the bottom so you can attach the speaker to bicycle handlebars, a kayak or a beach umbrella. A claw-shaped clamp, sold separately for about $20, lets you mount the speaker almost anywhere you want it.
The speaker's shell has controls built into the surface and connectors tucked away behind rubber plugs. And the sound is deep and rich enough to replace those bulky old-style boom boxes left over from the 1990s.