Replaced the one in the head with the slightly thicker tinted lens from Catalina Direct. Takes 10 years off the boat's age. Will order three more after this trip
Recall a thread last year? specing two sizes of O-rings, both of which I have on hand. The old lens frame did NOT have O-rings, but the new lens had a recessed hole in the side fitting the locking lugs' outside circular fastener. The old lens had no recess.

The replacement was straightforward and although the locking lug levers do not seat fully in the horizontal position, the fit was snug and there were no leaks during a few recent torrential downpours.

For those of you who have already replaced their lenses, am I missing something here? Is there supposed to be an O-ring in the recessed hole, which I assume goes on the outside, presumably lubed with a light coating of silicone grease? It's not leaking now, but will that last?

Any suggestions, or a link to a thread, would be greatly appreciated.

Thanks.