Hon&Guan 5 Inch Duct Connector, Plastic 5 Inch Dust Collection Fittings Duct Flange For Heating Cooling Ventilation System, Black.

I bought this to use with a modular custom 6" exhaust vent duct for a portable AC unit in a dedicated, climate controlled media equipment closet, and it worked perfectly. My first portable AC unit in the closet quit working after about 5 years, so I had to replace it. Unfortunately, the new AC unit came with a different type of exhaust hose attachment, even though both units were LGs, and I stupidly built the first exhaust duct to last forever. Since I needed to recreate part of the exhaust duct because of the different AC exhaust hose attachment types, I upgraded the 6" inline exhaust fan I'd been using to help push the exhaust about 20' to an external wall, as I wasn't sure how much longer the original fan would last and they're relatively cheap. Additionally, I wanted to install a one-way butterfly baffle to prevent any cold air from coming back into the closet while the AC exhaust wasn't running, which I hadn't done before. And, because I've recently begun to fully appreciate that everything will eventually need to be replaced at some point, I wanted to make the exhaust duct as modular as possible, because connecting flexible ducts to portable AC exhaust hoses, inline fans, and one-way baffles is a time consuming nightmare. So, I added an insulated adhesive gasket between the two pieces of this duct connector, and superglued some screws onto one of the pieces, then used nuts to hold them together. This way, I won't have to tear the whole exhaust duct apart again just to replace one part of it, should something fail again (portable AC, inline fan, baffle, etc.).

Good quality but i returned it

I am using this to move warm air from a wood stove in the basement to in-floor air registers left over from a previous heating system. I built a baffle for each duct mounted in the basement ceiling above the stove and attached a 6-inch fan to one side of the baffle and one of these connectors to the back. The other end of the duct connects to the rigid duct that goes to the floor register. Once in place i get a nice steady flow of warm air into the living space on the main floor. This connector plus a 6-8-inch ring clamp cleanly attaches the flexible duct. It's a little fiddly to get on, more about how the duct is made than the connector. Stretch out the duct and it slides right over the connector, tighten the clamp and it stays in place.

This is a quality part it just didn't fit inside the 3 in flex pipe I was using. Found a similar one that was 2.75 in diameter and it fit perfect for my needs.

just what I needed

Good

Just what I needed

Cheap, thin plastic.