Rab
Rab Ionosphere 5.5 Sleep Mat (Regular, 183 x 51 cm)
Best use
- Made for
- Backpacking and wild camping, Winter mountain
Why these labels
- Backpacking and wild camping: The maker states this use, and the published specs do not rule it out.
- Winter mountain: The maker states this use, and the published specs do not rule it out.
From the maker's stated use and the published specs.
- Summer wild camp: 7/10 UK, roughly May to September, nights above about 8 °C, sheltered pitches.
- Three-season hills: 7/10 UK hills in spring and autumn. Wind, rain, and nights near freezing.
- Winter camp: 7/10 UK winter or high ground. Below freezing, strong wind, possibly snow.
- Weight: 6/10 How much it adds to your pack, compared with the whole market.
R-value 5.5.
Lowest price we found
£169.99 at Ultralight Outdoor Gear
Go to Ultralight Outdoor Gear Compare 2 shopsA warm, thick 8 cm air mat for winter camping, mountaineering and trekking where weight and pack size matter
- Valve
- two-way valve
- Type
- Air
- R-value
- 5.5 (not ASTM)
- Weight
- 615 g (Regular)
- Thickness
- 8 cm
- Size
- 183 x 51 cm
Packed size 2.7 L, 24 cm long and 12 cm across Compare with a 2-litre bottle
Shorter than a 2-litre bottle and a bit wider than one. Drawn to scale.
Where to buy
Ultralight Outdoor Gear £169.99 In stock. Free delivery. Free UK delivery over £15.
View at shop: Ultralight Outdoor GearRab £190 In stock. Free delivery.
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
Warmth
Estimate from maker's specs: maker's R-value (not ASTM tested) 8/10How well it stops the cold ground chilling you. 8: Clearly better than most.
Estimate from maker's specs
Thickness
From maker's figures 8/10How deep it is. Deeper is comfier, above all for side sleepers. 8: Clearly better than most.
8 cm thick.
Quietness
Estimate from maker's specs: mat type (fewer than 3 reviews about noise) 5/10How little it crinkles or squeaks when you turn over. 5: Does the job. Average for wild-camping gear.
No review we found says how noisy it is, so this is an estimate from the mat type.
Weight
From maker's figures 6/10How much it adds to your pack. 6: A bit better than average.
Rab gives 615 g for the Regular, in the 550-749 g band. Ultralight Outdoor Gear lists 661 g, also in that band.
Packed size
From maker's figures 6/10How much room it takes in or on your rucksack. 6: A bit better than average.
Rab gives a packed size of 24 x 12 cm: 3.1416 x 6 x 6 x 24 = 2,714 cm3, about 2.7 L, in the 2.5-3.9 L band.
In short
Good for
- A warm, thick 8 cm air mat for winter camping, mountaineering and trekking where weight and pack size matter
- Side sleepers who want a thick 8 cm mat, as Ultralight Outdoor Gear's reviewer found
Strengths
- Rab lists R-value 5.5 at 615 g for the Regular, with a heat-reflective lining
- 8 cm thick, with oversized outer chambers that keep you in the middle of the mat (Rab)
- 30D base for rough ground (Rab)
- Pump sack, two-way valve and repair kit included
Weaknesses
- Regular is 51 cm wide; the 64 cm wide version is Long wide only (196 cm)
- Rab rates lightness and pack size well, but not top marks
- Long wide packs larger (29 x 14 cm against 24 x 12 cm for the Regular)
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.