The G-Boom ($100)and G-Grip ($70) Bluetooth Speakers from G-Project are designed to take a beating in the outdoors. They can both withstand drops, getting tripped over and (in the case of the G-Grip) briefly getting mistaken for a dog's chew toy.
The G-Boom is an outlier compared to the Bluetooth speakers that we've checked out so far: it's really big (10 1/2" wide, a foot tall and 5" deep) and feels more like the carrying case for a power tool than it does a piece of audio gear (maybe it weighs 5 lbs. or so).
When you've got the G-Boom plugged in to charge, you can use its USB ports to charge your phones and tablets. The G-Boom promises 6 hours of battery life on a full charge and it definitely held a charge over the course of a week when it traveled with me and I used it in short 15-20 minute bursts.
The G-Boom is really loud, loud enough to bring back memories of '80s boom boxes. If you're looking for something to take to a cabin or a lake house and entertain a large group outdoors, this speaker really delivers a lot of performance for the price. G-Project speakers are developed by the same team that designs the Soundfreaq brand and they don't quite have the same audio quality as their cousins, but these are really aiming at a different market: the audio tradeoffs aren't going to make a huge amount of difference in an outdoor setting and this thing performed well with with Jason Aldean, Led Zeppelin and Rick Ross.
The G-Grip is about the size of a Jambox but it's available for about half the price. It comes with a sturdy strap and it's small enough to fit in an inside jacket pocket if you're taking it on a ski trip or on a long hike (7" wide x 2" high x 2" deep). Aside from its sturdy constructing, the best thing about the G-Grip is the large rubberized buttons that make it easy to figure out how to control the speaker without having to look at it (or put on glasses if you've got less-than-perfect eyesight).
The main selling points are the ruggedness and portability. You're going to get much better audio performance in the G-Boom (or in the $70 Sound Spot reviewed her earlier), but this device is aimed at users who need something that won't fall apart outdoors.
Both the G-Boom and G-Grip come with rubber covers to protect the power and audio ports. Neither offers speakerphone capabilities but that's not really a function you're likely to use much outdoors anyway. The Bluetooth pairing was solid and the G-Boom worked well at a distance of 10 yards outside (and it was loud enough to be heard at that distance).
If you need a loud speaker that will still look okay after it's been banged around outdoors or in your workshop, the G-Boom is a great buy at $100. And if you're going to really punish a pocket speaker, the G-Grip is one you won't have to replace anytime soon.