From Its In Form™ Fit System That Lets You Customize The Fit To Its Adjustable Venting That Provides Airflow When You Need It, The Ratio™ Helmet Lets You Make All The Adjustments You Need To Stay Comfortable On The Mountain.The Ratio™ Is A No-nonsense Helmet That Boasts Features Found On Premium Helmets At A More Accessible Price.Beneath the sleek silhouette, you’ll find the adjustability of an In Form fit system and Thermostat Control adjustable venting. Meanwhile, the Ratio helmet is also fully compatibility with aftermarket audio systems by Outdoor Tech so you can listen to your favorite tunes on the mountain.Construction:- Hard Shell Construction- Eps Foam LinerVentilation: - Thermostat Control™ Adjustable Venting - Allows Custom-tuning Of Airflow Instantly With A Simple, Low-profile Control Button On The Outside Of The Helmet- Stack Vent™ TechnologyFit System:- In Form™ Fit System - Easy To Dial In A Custom Fit In Seconds, Even With Gloves On. Ergo-friendly Dial At The Base Of The Helmet That Provides Up To 6cm Of Adjustment And - Enhanced StabilityHighlights:- Seamless Compatibility With All Giro GogglesSpecifications:- Product Weight: 590g (size Medium)- Electronics Compatibility: Compatible With Aftermarket Giro Audio Systems By Outdoor TechTechnologies:Stack Vent Technology:- Our Stack Vent was developed based on research showing the majority of warm air that cancause fogging comes from the goggle’s center top vent. Aligning the Stack Vent in the helmet with the center vent of the goggle helps keep it clear and fog-free.Thermostat Control:- Thermostat Control Adjustable Venting allows you to custom-tune airflow instantly with a simple, low profile control button on the outside of the helmet. No other system is faster or easier to adjust, and nothing is more effective at keeping you comfortable.Vertical Tuning:- Accommodates different goggles and head shapes for a custom fit free of gaper gapHard Shell Construction:- Hard Shell Construction produces great helmets at a great price. A rugged outer shell is molded and then attached to the EPS foam liner.Seamless Compatibility:- For optimal performance of both helmets and goggles, Giro products are designed to work together, ensuring a seamless interface between helmet and goggle for an exceptional fit and dependable, worry-free function.