Castelli Estremo Thermal Winter Cap

Front: Polartec AirCore fabric

This material blocks the wind at the front of your head, exactly where you are most affected by cold airflow under your helmet.

Why only on the front and not across the whole cap?

A cap that is equally windproof all over also traps the same amount of heat and moisture everywhere, which can cause overheating during intense exercise. To prevent this, Castelli combines two fabrics based on where they are most needed. The front of your head, which is most exposed to wind while cycling, features the wind-blocking Polartec AirCore fabric. The back of your head, which is less exposed to wind but does need to wick away heat and sweat, features the more breathable Warmer fabric. This follows the same logic as a winter jacket with a windproof front panel and a more breathable back panel.

Back: “Warmer” fabric

This fabric allows sweat to escape, so your head doesn’t stay damp despite the warmth retained by the cap.

Full ear coverage

The cap is designed to fully cover your ears, one of the areas that gets cold quickest on winter rides.

• The coldest winter rides, when you need maximum protection against wind and cold;
• Use under a cycling helmet thanks to its low weight and thin construction.

• Mild or cool weather, when a thinner, more breathable cap will be more comfortable.

• Wash the cap at a maximum of 30°C for best care of the Polartec AirCore and Warmer fabrics.
• Leave to air dry; the tumble dryer will damage both materials.