From the manufacturer

The reigning king of full-face helmets, the D4 range expands with a Polyacrylite model packing the same safety and comfort features as the premium carbon and composite models into a price-conscious shell. Details make the D4 the most coveted full-face in mountain biking, including Mips® C2 brain protection, an air intake system for ventilation, and an unmatched anatomical fit.

Specifications

• Mips® C2 Rotational Impact Brain Protection System
• Advanced Polyacrylite shell construction
• Front air intake system, with high flow through polymer center and power grid side mesh
• Collarbone Suspension System
• Breakaway visor screws
• Anti-microbial padding
• Quick release contoured 3D cheek pads for anatomically optimized fit