ORIGINAL: mfd1027
Both open. Increases your FOV, makes it a lot easier to shoot under low light conditions and I think it helps with target panic. Now of course you have to be rt. eye dominant for a rt. hand shooter and left eye dominant for a left hand shooter to be able to do it.
Dan
I dont think thats accurate. My buddy is left eye dominate and shoots right handed, shoots with both eyes open and he is an awsome shot.