The way this mounts to the ocular, it brings the scope much closer to your eye even when the cover is open. This is a bit of a problem for the Kahles 624i, which isn't god's gift to eye relief, and creates a feeling of a tunnel. But it holds on super tight and you get used to it.

These are tough, durable, protect the lens well, and so far have not flown apart on my 50 BMG like certain other brands. I think they will hold up a good, long time. No regrets!