Columbia calls Omni-Heat Thermal Reflective. The principle is the same as a reflective space blanket, the idea being that the inner surface reflects your body heat back giving increased warmth while keeping bulk low. It looks a bit Space 1999, but the inner

The print on the inside of the collar of Columbia's Omni Heat Heavy Weight Long Sleeve Top reads 'Make Your Own Heat' and that, in a nut-shell, is what it's all about.On the outside it looks normal enough, but on the inside, Omni Heat fabric

Columbia's latest technology, launched this winter 2010, is called Omni-Heat and the company's hit YouTube with a selection of videos intended to convey the message that, well, it keeps you warm, even if you insist on skiing behind a snowmobile

with fuel pump.The Primus OmniFuel Ti will be available in early 2012 and retails for 199.95 euros, UK price to follow.More details at www.primus.se.

-Dry and, of course, 'non-Omni' OutDry for starters.Technology CrazyThe brand is technology crazy. Which other major outdoors company would produce a base-layer top with a silvery, reflective inner surface to radiate heat back to the user? It's gear geek

stove, so it may make a better than usual effort at the gas burning.Weight is a claimed 176g, output 1500 W, boil time 4.5 mimutes per litre and it will retail for £100 once it launches in early 2012.More Primus info at www.primus.se.