Here’s a minimalistic approach to a speaker if we ever saw one. It was designed by Hironao Tsuboi for Kent of British American Tobacco. The Vol is a volume knob with a speaker built in. Obviously this makes the Vol speaker very portable.
In fact the only way of controlling it is the dial on top. You use it to switch it on and off and to adjust the volume. If it makes it to market, the USB rechargeable speaker will be made out of aluminum and measure just 2.2 inches in diameter and 1.4 inches in height.