I cant tell you how high they go, I have never seen one in the flesh but my Ranger 1 is very well made.
No I cant see it on the website but I don't think I could before. I had seen on advertised on eBay that had sold out. So I gave RUAG a call, they sent the wrong one to my local gunshop. After a bit of toing and froing, I called Tier one who gave me the part number. It was then sorted quickly.
I am sure that if you give T1 a call they will sort you out. I am sure RUAG must have loads if T1 no longer stock them, because they are the most under-advertised useful bit of kit that I know of.
Here's my FB Post
Facebook Groups in Bergara Enthusiasts.