Not so strong, but still okay

1) The Speaker may suitable for outdoor use (so it writes the manufacturers also) but I doubt that the supplied power supplies comply with the IP standard. I find neither on the power supplies even in the manual to information. Only this information in the manual, Quote: The system is designed for indoor and outdoor use (splashproof). Subsystem I understand that all the system related parts are splashproof. Maybe I'll try it a try.
2) The promised 100 meters are not complied with. "Quote Manual: transfer up to 100 meters through walls and ceilings.". I use the speakers like in my about 20 meters away, garage, plus two walls. It comes despite repeated channel selection (2.Kanäle with automatic scan) interference.

3) The sound is ok If you want something better has to spend at least twice. Well the mono / stereo switch is to be made to each speaker. So you can operate the speakers individually. The "Bass Boost function" raises moderately to the depths.

4) The speakers can also be operated with 6x AA batteries. The batteries will last about 3-6 hours depending on the volume and distance to the transmitter.