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AlpinSpirit three-season mummy bag, 300 GSM fill review

A three-season mummy bag that publishes weight, packed size and fill density, and puts its comfort range at 15 °C to 20 °C with no standard behind it.

The bottom line A well-measured summer and shoulder-season bag: weight, pack size and fill materials all on the page. The temperature claims are the weak part, and the 0 °C line should be read as a remark rather than a rating.

What this listing puts on record

A mummy cut at 210 × 75 cm, a 300 GSM fill of cotton and hollow fibre, a comfort range of 15 °C to 20 °C with a note that the bag is also usable at 0 °C, a weight of about 1300 g, a packed size of about 35 × 25 cm reached with compression straps, a water-repellent hard-wearing outer, and two-way zips that open from top and bottom.

The two temperature claims

15 °C to 20 °C is the comfort band the maker publishes. 0 °C appears in the same bullet as a further claim of usability.

Those two are fifteen degrees apart and no standard sits behind either. Under EN 13537 or ISO 23537 the comfort figure would be a single temperature from a heated-mannequin test — an indication, not a promise. Here it is a description, and the 0 °C is a remark alongside it.

The fill, named

Cotton and hollow fibre. Naming both is unusual and useful. Cotton is pleasant against the skin and heavy; it also holds moisture and gives it up slowly. Hollow fibre is the synthetic that does the lofting.

The two numbers that matter for carrying

About 1300 g, into about 35 × 25 cm with the straps pulled. Both published, both in the same bullet, which makes the carrying decision straightforward for once.

Before ordering

210 × 75 cm is a compact mummy. If you are over about 185 cm tall, check the length against your own before the hood becomes the reason it does not work.

Availability

Selling between 40 € and 53 € across the German, Italian and Spanish Amazon stores when this page was checked.

It also sells on the British Amazon store in the local currency, which the range above does not cover — that range counts euro stores and nothing else.

Catalogued on the French Amazon store with nobody selling it: the reference is there, the offer is not.

Nothing came back from the American Amazon store, so the buy link there opens a local search instead of a page that is not there.

Every figure in this section is what Keepa returned on the day this page was last updated. Prices and offers change without notice.

Prices quoted in this text were read on 6 September 2026. The live price is at the top of the page.

What it does well, and where it gives way

Strengths

  • Publishes weight and packed size together — about 1300 g into about 35 × 25 cm with the straps drawn
  • States the fill materials by name, cotton and hollow fibre, rather than saying insulation and stopping
  • Publishes its dimensions at 210 × 75 cm, and a two-way zip that opens from the top and the bottom

Compromises

  • The comfort range is prose with no standard named, and the added claim of use at 0 °C sits fifteen degrees below it with nothing to support it
  • 300 GSM is a fill density rather than the grams of insulation in the bag, so the fill weight remains unknown
  • A cotton content adds weight and holds damp longer than a pure synthetic fill, and no drying guidance is given

Specifications

Comfort ratingGiven as a range of 15 °C to 20 °C — an unstandardised figure
Limit ratingNot stated as a limit — the maker adds that the bag is also usable at 0 °C, which is not published as a limit figure and names no standard
Standard quotedNone named — neither EN 13537 nor ISO 23537 appears in the listing
Fill powerNot published on the listing — fill power describes down, and the fill here is stated as cotton and hollow fibre
Fill weightNo weight published — the maker publishes 300 GSM, a fill density in grams per square metre, not the grams in the bag
Down or syntheticSynthetic — stated as cotton and hollow fibre
Shell denierNot published on the listing — the outer is described as hard-wearing and water-repellent, with no fabric or yarn weight named
Baffle constructionNot published on the listing
Packed sizeAbout 35 × 25 cm — stated, reached with compression straps
WeightAbout 1300 g — stated, with no label saying what is counted
Amazon referenceB0FXCGGMJW (same reference on 5 Amazon marketplaces)
EAN4262554110048

What people ask before buying

What does cotton in the fill change?

Cotton is comfortable against the skin and takes on moisture readily, and it is slow to give it back. In a bag used on damp nights that means more weight carried and a longer dry-out. The listing names it plainly, which is more than most do.

How should the 0 °C claim be read?

As a separate sentence from the comfort range, and not as a tested figure. The maker publishes 15 °C to 20 °C as the comfort band and adds that the bag is usable at 0 °C. No standard is named for either, so the fifteen-degree gap between them has nothing published to explain it.