Rab Exosphere 3.5 Sleeping Mat – Long Wide

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Rab’s first foray into the self inflating mat market is an impressive attempt. It’s a good 3-season mat and very reasonably priced for such a good quality, light mat.

Rab says: 

If you’re looking for comfort, durability and ease of use, our self-inflating Exosphere 3.5 sleep mat is ideal. Its X-Core™ foam filling is supportive and insulating, ensuring you get a rejuvenating night ready for tomorrow’s adventures. This foam uses X-core technology which is a 3 dimensional weight relieved structure. This saves weight and reduces pack size, but also traps air to boost warmth and contributes towards the mats R-value of 3.4, while the rectangular shape supports a range of sleeping positions. The low-profile two-way valve allows for rapid inflation when the weather is threatening, and easy deflation when you’re ready to roll the mat away into its stuff sack.

Made from recycled polyester with a fluorocarbon-free DWR, the Exosphere 3.5’s outer fabric is hardwearing yet with a comfortable next-to-skin feel. This versatile and dependable sleep mat is ideal for a variety of uses, and is the perfect place for you to recharge and make tomorrow count.

Our Verdict

This is a nice thick self-inflating mat; it inflates very easily; just open the valve and wait 30 minutes; of course, it can be helped along with a few breaths of air. If you can get your hands on one of the Rab pump sacks (which I’m sure will soon be available to buy soon), the pump sack fits onto this valve, though I suppose that defeats the point of a self-inflating mat.  

The mat is rectangular, which I prefer over mats that taper at the feet; I always find that my legs have slipped off during the night on narrower mats, especially if I’m using a quilt. A rectangular mat will add some weight, but I’ll happily carry a few more grams for a good night’s sleep. It’s a nice quiet mat, so you won’t disturb your campmates tossing and turning during the night.

I like the roll-away stuff sack. It’s an ergonomic design that, in principle, works really well; however, as is usually the case, it could be a bit bigger.  Self-inflating mats ( I always find)  are a little harder to store away neatly.

– Reviewed by Ultralight Outdoor Gear

Features

• Self-inflating X-Core system is quick and easy to use
• X-Core Foam Technology with weight saving honeycomb construction boosts warmth, support and comfort
• R-Value: 3.4
• Thickness: 5cm
• Hybrid rectangular shape allows various comfortable sleeping positions
• Low profile two-way valve for easy inflation and deflation#Roll-away stuff sack and repair kit included
• X-Core Insulation (Polyurethane open cell foam)

Specifications

• Weight: 912g
• Dimensions: 196 x 64 cm
• R-Value: 3.4
• Thickness: 5cm
• Packed Size: 33 x 18cm

ASTM R-Value

From 2020, there is a new industry standard for measuring the R-value (level of insulation) of sleeping mats – ASTM F3340-18. This new standard is the sleeping mat equivalent to the EN rating for sleeping bags.

You can now directly compare the R-value of mats rated using the ASTM F3340-18 with confidence that is a fair and accurate comparison between mats. In simple terms, the higher the R-value, the warmer the mat.

In general terms, an R-value below 2.0 is for summer use, 2.0 to 4.0 is for cooler 3 season use and 4.0+ is for winter temperatures. This will be also be dependent on your sleeping bag, how cold you sleep etc. Please contact our customer service team if you need advice on choosing the right mat for your activity.

Material & Construction

• 20D Recycled polyester outer fabric with internal TPU coating and fluorocarbon-free DWR

Help & advice:

• The Ultimate Guide to Choosing an Ultralight Sleeping Mat
• Time-Saver Guide to Choosing a Sleeping Mat
• About Rab
• Rab Sleeping Mat Guide
• Rab Sleeping Mat Technology Explained
• Rab Sustainability and Responsibility
• R-Value Explained
• Recycled Content in Outdoor Gear