At 240 g total weight, the Cumulus Magic 100 Zip is the lightest bag in this Cumulus range — built purely for summer bivouacs and warm-night ultralight trips where every gram in the base weight matters. Just 105 g of 900-fill-power goose down (a notably high fill power, at a 98/2 down ratio) is enough to earn a manufacturer-rated comfort of 13 °C and limit of 10 °C, reflecting how little margin this bag carries for anything below mild summer temperatures.
Horizontal H-baffles keep the sparse down fill from shifting, and the full-length two-way zip runs down the left side. Packed size is just 18 × 11 cm at 1.6 litres — small enough to fit in a hip belt pocket on some packs. Internal length is 182 cm, shoulder width 75 cm, hip width 47 cm, so it suits shorter and more compact users best. This is a specialist bag: excellent for warm-weather minimalism, but with no meaningful cushion against a cold snap.
Specifications
Color
Green
Comfort Temperature
13 °C
Limit Temperature
10 °C
Temperature Rating Standard
Manufacturer rated
Season Rating
1-season (summer)
Total Weight
240 g (8.5 oz)
Fill Weight
105 g (3.7 oz)
Internal Length
182 cm (6.0 ft)
Shoulder Width
75 cm (2.5 ft)
Hip Width
47 cm (1.5 ft)
Packed Size ( Length x Diameter )
18 x 11 (7.1 x 4.3 in)
Packed Volume
1.6 l (0.42 gal)
Insulation Type
Goose down
Fill Power
900
Fill Power Standard
EU standard
Down/Feather Ratio
98/2
Shape
Mummy
Baffle Construction
H-baffle
Baffle Orientation
Horizontal
Zipper Side
Left
Zipper Length
Full length
Two-Way Zipper
✓
Warmth-to-Weight Ratio f(x)
41.7 °C/kg
Fill Efficiency f(x)
9.52 °C/100g
Weight per Degree f(x)
24 g/°C
Where to buy
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Category context Sleeping Bags (417 products)
Weight
Ultralight· mainstream zone 819–1420 g· ranked 2 of 418