Marmot Ion 20

The Marmot Ion 20 combines 850-fill-power goose down with Thermal R Micro synthetic insulation in a hybrid layout rather than one material throughout — a common way to place synthetic fill at moisture-prone points like the footbox while keeping down's warmth-to-weight advantage elsewhere. At 825 g total weight it sits in ultralight mummy-bag territory, with EN comfort rated at -2°C, a -8°C limit, and a -26°C extreme figure — broadly in line with dedicated down bags like the Helium 15, plus the added moisture resilience the synthetic sections provide. A 12/15-denier nylon mini ripstop shell with DWR treatment keeps weight minimal while resisting light moisture, and horizontal box baffles limit down migration. A draft collar plus draft tube, an adjustable contoured hood, and a full-length two-way zipper cover the cold-weather details expected at this temperature range. Cut for users up to 183 cm in a men's-specific fit, with RDS-certified down, it suits thru-hikers and alpinists who want down-level warmth-to-weight with less worry about a damp campsite.