This is a DOT Vented Wine Shorty Series DOT Motorcycle Beanie Helmet which is the lightest and smallest in the market. Three different shell sizes are used to make different sizes. There are no other helmets on the market that vent like this one. The Wine Vented Motorcycle Helmets are tested and keep you 20 Degrees cooler when opened.  This Motorcycle Helmet weighs approximately 30 oz and measures 8.5 inches from ear to ear and 10.5 inches from front to back. 
This has a new EPS liner which is only 1 inch thick compared to 1.5 to 2 inches you will find in other similar helmets