Exhaust ports & shell shape These top-diffuser-vent ports nearly double the XD-4's airflow, while its shell shape provides better aerodynamic stability at higher street speeds in concert with its high-flow peak and side cowl vents. The high flow peak reduces drag at highway speeds and helps direct air into upper intake vents for improved internal ventilation. 5mm peel-away side-temple pad Arai's exclusive peel-away side/temple crown pads give you the option of 10mm more interior width if needed. Brow vent faceshield Brow vents in the XD-4 faceshield provide airflow to the temple area of the head. Using the eye port to improve ventilation, avoiding additional holes in the critical forehead, Arai improves rider comfort while maintaining shell integrity and impact energy management performance. Fully removable/replaceable/washable interior Arai's Dry-Cool technology keeps you drier and cooler for greater long-haul comfort. Easily removed/replaced for custom fitting or thorough cleaning after a long ride, race weekend or a season of casual touring, the Arai interior makes it easy.