The Move M is a portable bluetooth speaker from NudeAudio that I've really enjoyed using! I'm guessing the "nude" portion of the name comes from the sleek, simple design. The speaker is lightweight (only 8 ounces) and has a rubberized cover on it. The included rope can be used to attach the speaker to your bag or hang off something on the wall, or even your beltloop.
NudeAudio Move M on Amazon - http://amzn.to/1aRdpg1