Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
The word "adjustable" threw me a little, too. If you're just asking about helmets that ventilate well, my Shoei X-11 vents very well. One vent up top, and one vent down low. Opens and closes on the front and the back.The vents on my Scorpion EXO-700 are excellent. "Adjustable" is too subtle if you ask me. Either open them or not. Need less airflow? Don't open all of them.
If you are looking for maximum venting, not to mention a rather "unique" look, check out Givi X.01. Here is a link:
http://www.givi.co.uk/helmets/
http://www.webbikeworld.com/r2/motorcycle-helmet/givi/x-01/