Ventilation system for more comfort to the rider while driving.. Studds Thunder Helmet With Mirror Visor duly silicon hard coated for scratch resistance properties. Washable and replaceable liner and cheek pads. Aerodynamic and Assertive design. Spare visor available in clear, smoke tint, mirror and rainbow options. Available in M (570 mm), L (580 mm), and XL (600 mm) sizes.