The Sea to Summit Ether Light XR is an insulated air pad that pairs ThermalCore reflective insulation with roughly 9.9 cm of Air Sprung Cell cushioning, giving an ASTM-tested R-value of 4.1 — enough for three-season backpacking including cool nights, though not a dedicated winter pad. At 470 g for a 183 x 55 cm sleeping surface, it's built for hikers who want real cushioning and warmth without the bulk of foam-cored designs.
Its weight-per-R-value of 114.6 g is a strong figure, reflecting how much insulation this pad delivers relative to its weight — a clear step up in efficiency from foam-core self-inflating pads. The included Airstream pump sack fills the pad without a separate pump or risking moisture from breath. This suits backpackers and thru-hikers prioritising low pack weight on three-season trips; anyone heading into sustained sub-zero conditions should look at a higher-R-value pad instead.