Sea to Summit Women's Ether Light XT Extreme Insulated

The Ether Light XT Extreme Insulated is the winter-rated pad in Sea To Summit's women's line, built around an R-value of 6.3 — high for an inflatable pad, and per the spec sheet good for four-season use including winter bivouacs. Insulation comes from a dual layer of THERMOLITE synthetic fill, and the Air Sprung Cell construction gives a 10 cm air layer between body and ground, double the thickness of a typical three-season pad. The women-specific shape widens at the hips (168 × 55 cm), and at 685 g the weight is reasonable for this level of warmth — a comparably warm winter pad without Air Sprung Cell construction usually weighs considerably more. Top and bottom fabrics are 30D and 40D nylon respectively, keeping overall mass down. A pump sack is included, which also keeps breath moisture out of the fill during inflation. Built for winter trekking and high-altitude expeditions where a high R-value is a requirement, not a nice-to-have — overkill and unnecessary weight for ordinary three-season trips.