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.
you will have to re tap the stock nut or replace it with a factory 870 nut (either way about 1 dollar worth of parts) there is a thread in canams forum about the sizing
I was able to put several different aftermarket stocks (Hogue, Knoxx, Remington) on my Grizzly and HP9 without problem. I wouldn't do any tapping or nut replacing until trying it yourself.