Hell of a surprise ;)
Conclusions: +: Very nice design, fits on every wrist, low power consuption, great app (tested on Android), display visibility, outstanding price. You will love it ! -: Missing support for Viber notifications (but it have We Chat support) For 1500 CZK (60 EUR appx), go for it. Very nice integration with manufacturer's app. Music controls works like a charm within VLC and Android built-in music app. I have been using them for 20 days and the battery drop is only 10 (!!!!) percent.