Factor 1 Base

These base layers are manufactured using patterns based on the Meraklon range. They should be worn snugly but not restrictive. Unisex leggings (no Fly) are only produced currently in this range.

Chest Inches 28-31 32-34 35-37 38-40 41-42 43-45
Chest CM 71-79 81-87 89-94 97-102 104-107 109-114
Back drop inches 24 26 28 30 32 33
Back drop cm 61 66 71 76 81 84
waist inches 26-28 29-31 32-34 35-37 38-40 41-42
waist cm 66-71 74-79 81-87 89-94 97-102 104-107
inside leg inches 24 27 28 29 30 31
inside leg cm 61 66 71 76 81 84
womens uk 6 8-10 12 14 16 18
womens european 34 36-38 40 42 44 46

Sub Zero Factor 1 Short Sleeve Unisex Base Layers


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Sub Zero Factor 1 Short Sleeve Unisex Base Layers are manufactured from tubular 100% polyamide fabric that eliminates the need for side seams on standard base layer sizes. If you require petite thermal underwear for women (XS) or plus size thermal underwear (XXL+) then the fabric has to be opened out and cut from different patterns. This means that flat side seams will be present. All of our Factor 1 base layer t-shirts have extra generous body lengths giving you a decent amount of fabric to tuck in to your trousers. This prevents lower back exposure when you bend over to tie your shoe laces or look for something in your backpack.

The shoulders on these lightweight base layers are closed using flat seam stitching to eliminate chaffing when wearing a harness or carrying a rucksack. The sleeves are constructed so they are set in to the body of the base layer, providing a much better fit round the armpits and the shoulders, maximising insulation and moisture transportation (wicking). They also finish just above the elbow and have a soft binding finish to keep the sleeve end snug on the arm. 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.

Sub Zero Factor 1 short sleeve unisex base layers are an ideal technical t-shirt for warmer weather or when long sleeves will be a hindrance to your activity. The simple design makes them compatible with most sports where you need to keep warm and dry, and the unisex style and in built stretch allows a snug fit to most body shapes. They are especially useful for rowing, canoeing, and cycling, and can be used in combination with the Sub Zero Factor 2 thermal mid layers for extra warmth in extreme conditions.


Made in: England

Sun protection factor: 50+

TOG rating: 0.42

Fabric: 100% Polyamide

Average weight: 140g / 4.9oz

Fit: Unisex snug

Layer: First - next to the skin

Size availability: XSmall-2XLarge

Colours: Black, White, Khaki, Cobalt blue

Fabric treatments: Hydrophilic impregnated

Washing instructions: 40°C wash with mild detergent, do not tumble dry, iron on low setting


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