eBay
New classic style polished stainless steel BBT Brand butterfly vent.  Measures 4" in diameter.  Perfect for cockpit lockers, companionway boards, locker doors, anchor locker etc.  Anywhere you want to vent, but also close when necessary.  Unique friction latch keeps vent where you set it.  Mounting holes are 2 5/8" on center.  Easy surface mount installation.  Our price includes free next day shipping, a money back guarantee, & no tax.   Check out my other items!   Be sure to add me to your favorites list!   Thanks for looking, Capt. Bob