It's even better. There's no need for it to 'adapt' or vent. It is a quick release spout. You simply push it into the fuel hole and it then releases the fuel, and it stops when you are full.
If there's extra pressure inside the fuel canister, it simply fills your chainsaw tank faster - no extra mess or splash as the nozzle has to be inside the tank before it releases the fuel. You only have to unscrew it to fill it. If there's pressure, and you want to refill it, just push the nozzle to release some. Very Nascar-like. Built to last forever, and worth every penny(and they aren't cheap).
Go to :40:
No one flips the spout out on them like you see in the vid- usually it stays in the ready to use position. He seems to be doing it mostly to show how it also stowes away flush if you need it to.
There's a newer version out, but I haven't used it yet.