Crye Precision Air Frame Ballistic Helmet.
This example was purchased in Europe last year from a serving French soldier who used the helmet in Africa during trails. The condition is very good and complete with just the slightest of use. Inside has its complete cushion liner and chinstrap system, no makers details to be found. As for size , well it fits my head so would say large. You might notice in the photos the round dent to the back left side, this was caused according to the soldier by a spent round hit during a certain action in Africa, saving him from one hell of a headache!
Just as an extra note, the helmet weighs just over 1.3 kilos, thats around 2.8 pounds with rails and mount making its an XL size. This is a level IIIA and was produced with the intention of reducing overall weight by using newer materials. These helmets can be found for sale by a few security suppliers including this exact model without marked rails, Compass Armour being one.