Men's Thermoactive Sweatshirt 4F M103 Navy Blue S/M

On a crisp autumn morning trail run or a chilly evening at the climbing gym, this men's thermoactive sweatshirt from 4F keeps your core warm without weighing you down. The navy blue base layer in size S/M is cut for a regular, athletic fit that layers easily under a shell or works solo during high-output activities.

Key specifications

• Thermoactive polyester blend fabric with moisture-wicking and breathable properties
• Insulating and warm, ideal for autumn and winter training
• Long sleeves with round neckline for classic coverage
• Flatlock seams reduce chafing during repetitive movement
• Stretch fabric allows full range of motion
• Discreet 4F branding on chest
• Colour: Navy Blue
• Size: S/M
• Gender: Men's
• Intended use: sportswear, base layer, outdoor activities

Why choose it

Engineered for active layering, this sweatshirt manages moisture efficiently so you stay dry and comfortable from warm-up to cool-down. The flatlock construction and stretch blend mean no irritation, even during long sessions. Its thermal properties provide reliable warmth without bulk, making it a versatile piece for training, hiking, or everyday wear in cooler months.

Ideal use cases

• Running and trail running in cool weather
• Gym workouts and fitness classes
• Hiking and outdoor adventures
• Base layer under a jacket for skiing or snowboarding
• Casual wear on chilly days

Good to know

Part of the 4FAW23 autumn/winter collection, this sweatshirt combines performance fabric with a clean, understated look. The regular fit accommodates a range of body types, and the S/M size is suitable for men who typically wear small or medium. Follow care instructions on the label to maintain the fabric's thermoactive properties.