The Xcelcius range of underwear is designed specifically for extreme conditions, manfuctured with different levels of protection . Ranges available to buy online: Starting with Poly-Vee, which is extremely lightweight underwear. This range is comfortable and ideal for those normal winter nights. Supertherm is made from Viloft orginal fibres and will provide the wearer with thermal protection down to -5°C. Comfortable and lightweight.  Please see our section on thermal & wicking properties Next in the range is Ultratherm. Again this is made with Viloft orginal fibres, brushed on the inside to provide an extra degree of warmth. Ideal for people who are constantly in environments between -1°C and -15°C     Please see our section on thermal & wicking properties for more information. Last in our Xcelcius range is Megatherm. Super Brushed and also thicker than the other levels, the Megatherm range is manufactured to protect in conditions as cold as -25°C     Please see our section on thermal & wicking properties for more information. Other ranges available are: