The reticles provide a very fine aiming point, either the top of the delta, or the slanted T of the crosshair. The crosshair also has hashmarks at 8 moa intervals on the verticle. I use 2.75-3.0 readers, but can see these very sharply with no correction at all. There are a bunch of YouTube videos about these, mostly positive, though one guy wrote them off pretty quicky without a fair trial I think. For best results you need both eyes open, and some folks can't seem to do that. The sight is usable with one eye, but that requires placing the reticle at the very top so the target sits just over it. Neither of my eyes is strongly dominant, so I can shoot with both eyes open using either, but some days that takes considerable concentration. I suspect this thibg is usable at whatever distance you can get a good sight picture.
With red dots, a little correction, +1 to maybe +1.5 gives me the sharpest image, pretty much what works best for distance vision, but I can get by without. I've been looking at the prism sights too and think that where they fit as to eye-relief, they're a good choice. The See All, like red dots, has unlimited ER and no parallax (effectively, also like red dots). They have a 30 day return policy too, plus a lifetime warranty. Still early to say for certain, but these look like a good alternative to red dots for some uses, are battery-free, and very small, light and rugged. How fast
I can be using them remains to be seen.
