The use of smart phones is uneingeschränt possible.
The Galaxy SII GT I9100 can be pushed well with practice. However, one should not use a screen protector, as this remains within "stick" to the window during insertion.
The bracelet also keeps rain away the moisture. After the sport should be allowed to dry the bracelet, otherwise formed under circumstances (for heat differences inside / outside) condensation water on the inside of the viewing window.
I use the bracelet now almost always when I'm on the slopes.