Who makes them

I’ve seen several pics around of rifles with scope mounts that are a one piece base unit with scope rings mounted to them. And whoever makes them, are they available in high or extra high mounts to get the scope up high enough to not have to lay your head sideways on the air tank to see through the scope?

May have to opt for a high set and the airforce tri-rail base if nothing else, just would feel more comfortable without having things stacked on top of things.