This fits standard 4in dryer hose just cut then get the hose clamps to rejoin.

Air Gate. - Ok, I live in Canada and -40s are not uncommon so my work space is in the garage and it has a heater, But the ventilation is straight out, and cold air will fall back down the vent tube. this is not good for the Laser. I made a Guillotine style air gate, so freezing air can become stopped farther away from the laser.