Factor 1PLUS base layer tops offer excellent moisture management whilst still keeping you warm, making them some of the best thermals to wear next to your skin. Manufactured from super soft 100% polyamide fabric, these base layer tops utilise body mapping technology to construct innovative seamless body forms, enabling features such as stretch rib zones for support and waffle zones for enhanced heat retention and greater perspiration control.

The only seams present on these base layer thermal tops are on the sleeves and the shoulders where they incorporate other design features. The set-in sleeves provide a much more tailored fit in the armpits, maximising insulation and moisture transportation (wicking), whilst the seam on the sleeve length allows the addition of a thumb hole near to the cuff. This allows the wearer to place further layers on top of the base layer without the sleeves riding up, and can also protect the palm of the hand from cold weather. The round neck has been designed so that it stretches when placed over your head and its low profile also means it is not prominent when worn under clothing. The long body lengthgives the wearer a decent amount of fabric to tuck in to their trousers. This helps to avoid lower back exposure during activities and when sitting down.

These Sub Zero tops are one of the best lightweight thermal underwear ranges for general outdoor use. The simple design makes them compatible with most sports where you need to keep warm and dry. They cross over in to anything from skiing through to hiking and camping, and can be used in combination with the Sub Zero Factor 2 thermal mid layer range for extra warmth in extreme conditions. SUB ZERO FACTOR 1 PLUS LONG-SLEEVE TOP