Rab
Rab Alpine Bivi bivvy bag (230 cm long)
- Weight: 8/10 How much it adds to your pack.
- Rain protection: 9/10 How well the fabric keeps out heavy, long rain.
- Packed size: 8/10 How much room it takes in your rucksack.
Fast and light alpine routes and mountain-marathon style trips where 440 g matters
- Style
- Flat
- Weight
- 440 g
- Fabric
- 15,000 mm
- Floor
- 10,000 mm
- Membrane
- Pertex Shield Air 15D 3-layer
- Inner length
- 230 cm
Packed size 2.8 L, 25 cm long and 12 cm across Compare with a 2-litre bottle
About as long as a 2-litre bottle and a bit wider than one. Drawn to scale.
Where to buy
Ultralight Outdoor Gear £249.99 In stock. Free delivery.
View at shop: Ultralight Outdoor GearAbsolute Snow £189.95 Out of stock. Shop page says currently unavailable. Free delivery over £100.
View at shop: Absolute SnowRab £300 Out of stock. Out of stock when checked (Olive and Horizon).
View at shop: RabPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Weight
From maker's figures 8/10How much it adds to your pack. 8: Clearly better than most.
Rab gives 440 g, in the 400–599 g band. Ultralight Outdoor Gear lists 452 g without the stuff bag, in the same band.
Rain protection
From maker's figures 9/10How well the fabric keeps out heavy, long rain. 9: Among the best you can buy for this.
Rab gives 15,000 mm hydrostatic head for the 15D Pertex Shield Air upper, in the 15,000 mm+ band. Rab lists its only other fabric, a 40D PU-coated ripstop nylon it calls the 'Lining', at 10,000 mm, and says the bag has a waterproof bathtub base with taped seams. A single-skin bag has no inner lining, and Backpacker and Ultralight Outdoor Gear both describe the 40D nylon as the floor, so the floor is read as 10,000 mm, over the 2,000 mm line, and nothing is taken off.
Packed size
From maker's figures 8/10How much room it takes in your rucksack. 8: Clearly better than most.
Rab gives 25 cm x 12 cm: 3.1416 x 6 x 6 x 25 = 2,827 cm³, about 2.8 L, in the 2.5–3.9 L band.
In short
Good for
- Fast and light alpine routes and mountain-marathon style trips where 440 g matters
- Wet UK nights under a tarp or in the open, with a 15,000 mm upper and a bathtub base
- Cold-weather nights where a lighter bag than the Storm Bivi is wanted
Strengths
- 15,000 mm hydrostatic head on the upper, the top band for rain protection
- Light at 440 g and packs to about 2.8 L (25 x 12 cm)
- Air-permeable Pertex Shield Air upper, Rab's own figure 20,000 g/m²/24 h breathability
- Waterproof bathtub base with taped seams
- Wide zipped entry with an external storm flap
Weaknesses
- Flat bag with no pole, so the fabric rests on your face and sleeping bag when zipped up
- The 40D base is only 10,000 mm, lower than the 15,000 mm upper
- No independent test of the current model was found, so condensation, comfort and durability are estimates, not reviewed scores
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.