You have to look for it in the Limited Distribution section at the bottom of the Vortex home page. That one is a Midway exclusive. I've debated it, but I think that it's a crap reticle. For just a little more money, you've into the Nightforce SHV 3-10, a better scope.
I had a 3-15 when they came out. Glass was green/cold to me. Turrets were mushy. Just seemed meh so I returned it. I think it was Ilya's pick for a minute so I think I followed him in.
I haven't bought anything Vortex in a long time after going to Nightforce and Trijicon but this scope does check a lot of boxes. I have been eying it for a while now. I have the non-illuminated version of this reticle in the older 1.5-8 LH model and actually really like the reticle for hunting. It's on a 6.5 Grendel AR and I have killed a ton of stuff with that setup. I do agree with the comment above about the 3-10 SHV and for about the same price I would probably just buy another one of those instead.