The Formula line of helmets (designated "FN") takes the concept of lightness further by eliminating the integrated accessory ports on the side of the helmet. This gives absolutely the lightest full-face Formula style helmet in the world at just 2.58 pounds. The FIA 8860 Helmet homologation standard is meant to standardize helmet specifications for professional racing series. Most racers will not need helmets that conform to these extremely stringent regulations. Please check your rules to see if you need an 8860 helmet. Also available with earmuffs that provide a significantly quieter environment for the driver by aurally isolating the ear. The pressure upon the head can be adjusted by replacing the special foam rubber pads placed between the earmuff and the helmet. The earmuffs unique shape ensures they stay in place and do not make the helmet difficult to put on or take off. EPS cheek pads provide the best in lateral crash safety, while retaining the functionality of the earmuffs to provide a comfortable aural environment for communication. Visor Options: The ST5 FN Carbon 8860 comes with a 3mm clear visor for the absolute best in protection. For spares, you may choose from clear, yellow, smoked and iridium shields for driving in different lighting circumstances. All Visors mount with two specially machined aluminum fasteners and provide an air-tight seal with the rubber grommet on the helmet, can also be purchased separately. Aerodynamics: Front, rear, and IndyCar aero kits are available as add-ons FHR Posts: M6 nut pre-installed for easy FHR installation Two Shells: Stilo has two separate shell sizes for this helmet. This allows us to make a better-fitting helmet that is lighter weight. Instead of filling a very large shell with lots of padding for a size small, we have one shell size for x-small to medium, and one for large and x-large.