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Images: Marmot and its retailers. Used for product identification.

Marmot

Marmot Hydrogen

740 g of 800+ FP goose down, ISO-tested comfort 2 °C / limit -3 °C, from about £359 in the UK.

Weight
740 g
Comfort
+2 °Cbrand's own figure
Packed
31 × 15 cm

Best price found

£358.90

at Hardloop · In stock · RRP £449.90 · was £449.90

View Deal
  • AlpinetrekIn stock · RRP £409.95£368.96View Deal
  • Ultralight Outdoor GearIn stock · RRP £439.99£399.99View Deal

Prices checked 31 October 2026. We may earn a commission on these links.

  • 800+ FP down
  • Hydrophobic down
  • RDS down
  • Recycled fabrics
  • Second vent zip

Specifications

Weight
740 g (regular (fits to 183 cm); UOG lists 725 g excluding sacks)
Packed size
31 × 15 cm
Comfort
Comfort +2 °C / limit -3 °C
Fill
800+ FP goose down, 320 g fill
Shell & construction
Outer: 100% recycled nylon (Pertex). Lining: 100% recycled nylon plain weave; curved baffles, wrap-around foot box
Rating Standard
ISO tested (standard number not stated by maker)
Fill Note
RDS-certified goose down with ExpeDRY water-repellent finish. Marmot lists extreme -19 °C and a recommended use temperature of -1 °C.
Season
3-season
Zip
Left main zip (UOG lists 3/4 length) plus fold-down second zip
Manufacturer page →

Pros & cons

  • UOG calls it 'lighter and more compressible than many of its competitors'
  • Fold-down second zip lets you vent or sit up in the bag, per Marmot
  • ExpeDRY-treated 800+ FP RDS down copes better with tent condensation
  • Partial-length main zip limits venting compared with full-zip bags
  • Slim mummy cut (155 cm shoulder girth) may feel tight for broad sleepers

Sources for this product

  1. 1Marmot EU product page
  2. 2Ultralight Outdoor Gear listing and verdict
  3. 3Alpinetrek listing
  4. 4Hardloop listing

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