Alpinestars SM3 Radium Helmet — Size S, Matte Gray

Engineered for motocross, enduro and off‑road riding, this helmet prioritizes ease of use, comfort and impact performance.

The thermo‑injected shell uses a special polymer blend with variable thickness to deliver an optimal balance of impact protection and low weight.

A patented low‑friction coating on the inner EPS liner reduces rotational acceleration from oblique impacts by acting as a slip plane similar to the brain’s cerebrospinal fluid.

The visor incorporates a release system designed to disengage at a predetermined force, helping to reduce loads on the neck during an impact.

Ventilation is maximized with 10 inlets and 7 exhaust ports to enhance heat transfer and rider comfort.

Construction combines engineered polymers and energy‑absorbing foams to provide durable impact management and reliable performance.