5.11 Black Tactical Thermal Underwear

Composition and fit: what's inside

• Composition: 90% polyester, 10% spandex
• Fiber: Coolmax Core Nap - smooth on the outside, brushed on the body-facing side
• Cut: compression, form-fitting, no fasteners or pockets
• Set: long-sleeve shirt with raglan sleeve and crew neck + pants (leggings) with full-length inseam
• Inserts: dark olive/khaki panels along the side seams of the long-sleeve shirt and along the outer thigh seam on the pants
• Seams: flat-lock construction - won't chafe during extended wear
• Temperature range: 0°C and below
• Care: wash up to 60°C without loss of shape or size

How to wear: from base layer to system

5.11 tactical black thermal underwear is designed to be worn directly on the skin. In moderate cold with active movement, it works on its own - wicks sweat and keeps skin from getting wet. In severe cold or when stationary outdoors, wear it under a fleece jacket or tactical insulator: thanks to the snug-fitting cut, there's no excess volume between layers. The hypoallergenic material is suitable for extended wear directly against the skin without irritation.

Coolmax Core Nap: what makes this thermal underwear different

Most budget thermal underwear simply "blocks cold" but accumulates moisture. Here's a different approach: the dual-component Coolmax Core Nap fiber has different textures on both sides - the smooth outer surface rapidly evaporates moisture, while the brushed inner surface retains a micro-layer of warm air against the skin. The polyester with spandex doesn't stretch over time and maintains its shape after many washes. This combination is what sets this set apart from simple synthetic alternatives without specialized fiber structure.