The UE Roll delivers 360-degree sound, and is designed to be even more portable than its bigger brothers - its petite, disc-shaped design measures 13.5cm in diameter and weighs just 12oz.
It costs £100, and comes in six brightly coloured and patterned finishes.
You can connect up to eight smart devices at any one time using Bluetooth (A2DP).
Don't worry if you have a music player that doesn't support Bluetooth - you can still play your tunes using the 3.5mm jack hidden underneath the waterproof flap on the underside of the Roll. There's also a micro USB port for charging.
Ultimate Ears claims the Roll's rechargable battery will last up to nine hours on a single charge, and that the speaker's Bluetooth range is up to 65ft.
You can wirelessly connect two Rolls together, thereby extending the Bluetooth range and doubling up on speaker power. You can also connect the Roll to a Boom, or to a Megaboom - but not all three together.
The UE Roll comes with its own app, which is available for free on iOS and Android devices.
You won't need the UE Roll app for streaming music, but its features include an alarm clock, an equaliser, the 'Double Up' feature that links up two Rolls together, and the ability to check the speaker's battery status.
As with the Boom and Megaboom, the Roll is waterproof. The IPX7 certification means it will survive splashes and being submersed in 1m of water for a reported 30 minutes. Perfect for a pool party, then.
It's also 'life-resistant', so you can expect the tough shell to withstand plenty of knocks and scratches.
There's even a marine-grade bungee cord attached to the back of the Roll so you can attach it to yourself or say, your bike, and always carry it around with you.
"Music is made for sharing, connecting and enjoying," says Rory Dooley, general manager of Ultimate Ears. "It transforms moments into something special, and we designed the UE Roll to be part of those moments. No matter where you are, or what you're doing, UE Roll is there to amplify any experience."
The UE Roll is available from Ultimate Ears' website.