Both eyes open w/o a peep. This was my hardest thing to not screw up. Practicing was easy but when shooting at a deer I thought about it too late and closed one eye like I did for years. Now, I'm pretty good at it and don't screw it up. For low light situations it's the best. I had the same issue with the peeps and switched to a light gathering one before I upgraded to the scope. The light gathering one worked good but was nothing compared to the scope.

I always said the scope works so well it should be illegal.