Eyeball Vent, 1 1/4" Anodized Black Aluminum, SteinAir
OD is 2" (hole size required for mounting).
These eyeball vents are far superior in their construction to those seen elsewhere are are of much higher quality. These are the highest quality vents that money can buy. For example, the Black Vents are 100% anodized aluminum...and unlike the overpriced and low quality vents produced elsewhere, these plack vents don't require a "Plastic Flange" because of metal to metal contact. That's a sign of poor quality construction with metal on metal contact. These high quality vents have a nylon/delrin busing encapsulated between the eyeball and the flange to protect the aluminum. On top of that , the larger vents sold elsewhere reqire a three inch mounting pattern... 4 bolts which is much larger than need be. With these vents you simple cut a hole, install the vent and tighten the plenum or retaining nut behind it and hook up the tubing.
These vents include everything needed for install...no need to try and cobble together your own plenum or flange for scat tubing. On the small vents you can just directly attach a 2" scat tube to the vent - and on the large vents they have 2" plenums. These will come with a "BAC" part number on them, but that's because they are normally for the cockpits of fighters... you can figure out what the initials are for.