Giro Ratio Helmet 2025 - Lightweight Bike Helmet for Men & Women - Cycling, Mountain Biking & Commuting - Adjustable Fit & Ventilation for Comfort & Safety

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.

Circumference: 55.5-59cm
Construction: Hard Shell construction, EPS foam liner
Ventilation: 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™ Technology
Fit 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 stability
Product Weight: 590g (size Medium)
Electronics Compatibility: Compatible with aftermarket Giro audio systems by Outdoor Tech
Certification: CE EN1077
Highlights: Seamless Compatibility with all Giro goggles