While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
I could be wrong but I think the brno 2e is basically a cz452 (slim barrel). The brno model 4 is a heavy barrel model. Not sure if any differences in receivers.