clamshell

I'm thinking of using my starboard side cockpit locker as a compartment for two 6V golf-cart batteries wired in a series. Knowing that these flooded cells will release hydrogen during charging, I want to provide some passive ventilation for this locker so as to avoid the build up of this...

All, Today I'm looking for one or two Wilcox Crittenden, cast bronze Clamshell vents, 1 1/2" X 1 1/2". These are a triangular in shape and look just like their more modern stainless or chrome plated brass replacements. I need four of them for a project on the boat and to date have only...