For me, the first charging only took about an hour and I hear now for hours my audiobook.
The controls are unusually large and somewhat chunky / stiff: That is probably connected with the fact that you use water-resistant materials and must seal gaps. In addition to the on and off switch and the Play / Pause button also controls basic sit for the music control on top of the Aqua Audio. One can make the sound louder / quieter and jump to the next or previous track. Another button allows you to accept phone calls.
The Aqua Audio has a very good price / performance ratio and thereby brings a real added value in that it can be used indoors and outdoors without having to make too much on the environmental conditions thoughts.
The only thing that bothered me a bit at the beginning, is the fact that you can use the acoustic announcements neither off nor regulate the volume. But you get used to it quickly and therefore deducted a star I do not consider justified because otherwise the device really is fun and has great value for me.