What is the mechnanism of adjustablev air...
What is the mechnanism of adjustablev air vent?
To be honest, it's nothing fancy. My Holt is not adjustable, but it does a great job of regulating my head temperature. It is well ventilated, but not too breezy. If you want something with a bunch of adjustable vents, look at the Varient Brim.
This is not to say that the Holt is a bad helmet. I have had mine for over a year and I love it. It is the best helmet for the money.
There is no adjustable anything with this helmet..just put it on and go. Vents make some nice music when you tilt your head into the wind)