BigJim, I don't know if you're looking at putting one on a springer.
If so, download the online catalog and you'll see that the Nighteater series are all Spring airgun rated.
I also talked to the guy who spec'ed those for Legacy. He said that it was a MUST that those scopes be built that way.
I read up alot on them and they seem to have good feedback and are said to have decent optics.