Down bags give a superior warmth-to-weight performance than synthetic-filled bags, but the drawback with down is that it loses its insulation as it gets damp.
Sea to Summit have developed their very clever, unique, 3D Nano technology to overcome the issue of down becoming damp either from the inside of the bag through moisture vapour or from the outside of the bag from rain or snow.
Moisture vapour, from the body, moves in the direction of warm to cold; through the down, through the hydrophobic non-woven silicon layer, then condenses on the outer fabric layer, the 'dew point'.
The key part of the Sea to Summit technology is protecting the high quality 850+ Goose down, keeping it dry at all times to maximise it's ability to keep you warm. The condensed moisture is then dispersed by the non woven silicon layer which prevents it working back into the down keeping the down dry. Dry down means a better performing sleeping bag day after day.
Sea to Summit sleeping bags took three years to design and test and have been made with a number of features to keep the user warm and dry at all times. For more details visit the Sea to Summit website.
Sea to Summit Sleeping Bags are available from Joe Browns in North Wales, The Outdoor Shop Stony Stratford and Macpherson's of Inverness. They must be seen to be believed.
See this product at the Joe Brown - Snowdonia shop