Confusing to be frank - Pulsar DN 50mm Cover Ring Adapter

I purchased the pulsar 50mm cover ring adapter to use with my Scar model 17 rifle that I use for shooting. I was going to use the adapter with my vortex rifle scope mounted on my scar model 17 rifle which is in caliber 308. I received the package from ups that was left on the front porch. It was packaged very nicely in a cardboard box. Upon unpacking the box I noticed that everything in the box appeared to be there. If it was missing anything I couldn’t tell. I have yet to use it because I haven’t had the time. I have been shooting my ruger 10-22which is one sweet gun. I bet this pulsar 50mm cover ring adapter will fit on the ruger rifle too.