The Oakley DRT5 is engineered, designed, and validated by mountain bikers, including a close collaboration with 3x World Champion Downhill racer Greg Minnaar, Oakley DRT5 with MIPS technology will give you the confidence to rip down technical descents.MIPS Technology:In a helmet with MIPS Brain Protection System (BPS) the shell and the liner are separated by a Low Friction Layer. When a helmet with MIPS Brain Protection System is subjected to an angled impact, the low friction layer allows the helmet to slide relative to the head. The MIPS BPS is designed to add protection in helmets against the rotational motion. The rotational motion is a combination of rotational energy (angular velocity) and rotational forces (from angular acceleration) that both affects the brain and increases the risk for minor and severe brain injuries. MIPS BPS has been scientifically proven to reduce rotational motion when implemented in a helmet by absorbing and redirecting rotational energies and forces transferred to the brain.