Bell 4Forty Air MIPS Helmet

MIPS, or Multi-directional Impact Protection System, is a slip-plane layer inside the helmet designed to reduce rotational forces that can result from certain angled impacts. It provides an extra layer of safety specifically engineered for mountain biking scenarios where crashes often involve glancing blows.

The 4Forty Air MIPS features an extended rear shell design that sits lower on the back of the head compared to traditional road helmets. This extra coverage is specifically intended to protect the base of the skull during aggressive trail riding and technical descents.

Yes, the visor is adjustable, allowing you to move it up or down to suit your preference or to accommodate goggles when you aren't wearing them. It stays securely in place once set, so you don't have to worry about it shifting during a ride.

With 15 vents, the helmet is designed to channel airflow effectively across the scalp. While it is built for durability and protection, the ventilation system is sufficient to keep you cool during moderate to high-effort climbs on singletrack.

To find your size, measure the circumference of your head just above your eyebrows. The Small fits 52-56cm, Medium fits 55-59cm, Large fits 58-62cm, and X-Large fits 61-65cm; if you fall between sizes, we recommend trying the larger size first to ensure the Float Fit system has enough range to adjust comfortably.