There are plenty of bluetooth speakers you can take outdoors; there are even some that are waterproof. However, the Hercules Wae Outdoor Rush takes it a step further. Not only is it dust and waterproof, but it's saltwater resistant. That means it's effectively ocean-proof, so you can take it to the beach without any worries that it might have a mishap.
The Wae Outdoor Rush can be completely immersed in saltwater with no ill effects thanks to the design of its grills, which are made to prevent saltwater corrosion. It comes with a built-in FM radio and can even charge your smartphone, making it a very useful piece of kit to have on trips out.