Castelli Pro Thermal 3 Skully

Castelli Pro Thermal 3 Skully – Thermal Under-Helmet Cycling Cap

The Castelli Pro Thermal 3 Skully is a lightweight thermal cycling cap designed to keep your head and ears warm during cool-weather rides. Made from soft and stretchy Thermoflex fabric, it provides comfortable insulation, good breathability and a close fit underneath a cycling helmet.

Its low-profile construction has minimal impact on helmet fit, while the contoured lower section provides effective coverage around the ears. This makes the Castelli Pro Thermal 3 Skully an excellent choice for road cycling, gravel riding, cold morning commutes and higher-intensity winter training.

Warm and Stretchy Thermoflex Fabric

The Thermoflex fabric feels soft against the skin and stretches to follow the shape of the head. It also helps move moisture away from the skin, providing the balance of warmth, breathability and quick-drying performance required during active cycling.

Designed to Fit Under a Helmet

Flatlock seams help reduce pressure and skin irritation, while the flat edge prevents the fabric from bunching underneath the helmet. The cap stays comfortably in place without creating unnecessary bulk around the head or ears.

Key Benefits

• Provides thermal protection for the head and ears.
• Soft, warm and stretchy Thermoflex fabric.
• Contoured shape provides effective ear coverage.
• Low-profile construction fits comfortably underneath a cycling helmet.
• Flatlock seams help reduce rubbing and pressure points.
• Flat edge prevents fabric from bunching underneath the helmet.
• Breathable and quick-drying performance.
• Reflective rear details improve visibility in low light.
• Unisex design suitable for women and men.

Who Is It For?

The Castelli Pro Thermal 3 Skully is ideal for cyclists who need more coverage than a conventional headband but still want a thin and breathable layer underneath their helmet. It is suitable for road cycling, gravel riding, commuting and training in cool transitional or winter conditions.

Technical Features

• Product type: thermal under-helmet cycling cap.
• Main fabric: Thermoflex.
• Material composition: 52% polyamide, 32% polyester and 16% elastane.
• Fabric properties: warm, soft, stretchy, breathable and quick-drying.
• Construction: contoured to cover the ears.
• Seams: flatlock construction for improved comfort.
• Edge: flat finish designed to prevent bunching underneath a helmet.
• Visibility: reflective details on the back.
• Fit: regular.
• Gender: unisex.
• Size: one size.
• Weight: approximately 39 g.

When temperatures begin to drop, the Castelli Pro Thermal 3 Skully adds useful warmth without the bulk of a heavy winter cap. It is comfortable, easy to pack and practical enough to accompany you on every cool-weather ride.