Lightest1 / 3
Images: Rab and its retailers. Used for product identification.
Rab
Rab Ark Emergency Bivi
The lightest bag on test from a British mountaineering brand.
- Weight
- 105 g
- Thermal
- Reflective
- Packed
- 12 × 6 cm
Best price found
£18
at Rab · In stock · RRP
- RabIn stock · RRP£18View Deal
Prices checked 31 October 2026. We may earn a commission on these links.
- Waterproof
- Windproof
- Heat reflective
- Taped seams
Specifications
- Weight
- 105 g
- Packed size
- 12 × 6 cm
- Material
- Lightweight polyethylene, taped seams
- Thermal claim
- Reflects body heat; windproof and waterproof
- Open size
- Single person
Pros & cons
- 105 g and the size of a fist
- Stuff sack included
- Two-person version available
- Stock at other UK shops is patchy
- Thin material
More emergency bivvies
Full comparison →
5 photosBest all-rounderSurvive Outdoors Longer
SOL Emergency Bivvy
The benchmark reflective bivvy: sealed seams, 90% heat return, and a rescue whistle.
- Weight
- 108 g
- Thermal
- High reflective
- Packed
- 13 × 8 × 2 cm
- Waterproof
- Windproof
- Heat reflective
- Whistle included
- Reusable
Full specs, 3 retailers →View DealFrom
£19.99
at Needle Sports
2 photosBest value reflectiveLifesystems
Lifesystems Heatshield Thermal Bag
DofE-recommended metallised bag that packs smaller than a drinks can.
- Weight
- 110 g
- Thermal
- High reflective
- Packed
- 7 × 6 × 6 cm
- Waterproof
- Windproof
- Heat reflective
- Taped seams
Full specs, 3 retailers →View DealFrom
£10.95
at Cotswold Outdoor
10 photosBest for twoLifesystems
Lifesystems Survival Bag
The heavy-duty orange polythene bag every UK mountain leader carries.
- Weight
- 290 g
- Thermal
- Barrier only
- Packed
- 10 × 18 × 3 cm
- Waterproof
- Windproof
- Fits 2 people
- Reusable
Full specs, 3 retailers →View DealFrom
£5.99
at Cotswold Outdoor
