Impressed by the power of this little box

The main feature of this speaker is to be completely sealed IPX65. Personally I do not take my shower but it is a good companion for the beach because in addition it is not too heavy or too bulky. I wanted to increase the volume on my smartphone but now I am impressed by the output power, impossible to stay off when the volume is thoroughly and there is no distortion. Without good stereo effect secure the loyalty of treble and bass is well respected. This is probably due to the use of a passive radiator on the back in addition to the front speaker.
Furthermore it is possible to provide additional load to its smartphone by connecting it to the USB connector marked "OUT". This output provides a current of 1A. All connectors are protected by a rubber cover, a little hard to remove but this is for sealing.
Attention unlike other models, it is not hands free, there is no microphone. I guess it is because of the seal. If an appeal means the sound in the speaker but you must speak into the microphone of the phone.
Small flat, in the description there is talk of a wrist strap but this one does not find himself in the box or in the list of what is included?
I am nevertheless pleased with this speaker, it puts a good atmosphere at our barbecue with friends and not miss a call.