Buy from Amazon.co.uk : http://www.amazon.co.uk/gp/product/B00ED757QI?tag=1001consej026-21
Under Armour Men's ColdGear Infrared Tactical Fitted Crew - Black Medium
ColdGear Infrared uses a soft thermo-conductive inner coating to absorb and retain your own body heat
Dual-layer fabric gives you a soft warm interior and a smooth fast-drying exterior
Quick-dry fabrication keeps you light and comfortable
Smooth chafe-free flatlock seam construction
Sits close to the skin for a streamlined fit without the squeeze of compression