DLA stands for Dual layer Aerodynamics
This means the helmet has multiple surface treatments for optimal aerodynamics. The helmet exists out of 2 parts: a front glossy surface and a back matte dimpled surface. The front smooth glossy surface provides the best possible airflow and the least resistance in the area where the helmet first makes contact with the air. Front vents allow the air to flow through the front part of the helmet and around the head to keep the rider cool. This heated air escapes out of the back vents where the air gets trapped on the matte dimpled surface. This low pressure area helps to pull the cooler air over the front smooth glossy surface of the helmet. At speed the helmet will actually help pull itself through the air.