I normally don't listen to music on my boat, so I don't have a fancy sound system, but every once in a while I'd like to hear a nice tune. In my cruising area - the San Juan and Gulf Islands - I am in cellphone range most of the time, and can get sufficient bandwidth for Spotify. So I did a little research and got the DOSS SoundBox Touch Portable Wireless Bluetooth Speakers on Amazon for $28. I think they (it's a single unit with two stereo speakers) sound pretty good. It ain't high fidelity, but it's really not bad. The bluetooth connection to my iPhone has never failed, and the unit is easily recharged from a USB port. I strongly recommend this item.