In reply to Dave Perry:
I just bought another from Germany, strong pound and all that, £26. It goes on my helmet at the start of the season and off at the end, it folds back into a fairly bulkless position on top of the helmet for the bag, goes to the visor when the helmet is on that stops stuff being dropped from above, but doesn't get in front of the eyes, and comes down over the eyes if I worried about tools pulling, miserable weather, swirling spindrift, etc.
I damaged both eyes a few years back, one was chipping a bit of ice into an eye on an ice route so I am a bit cautious now.