A second wave of shock has arrived from the UK on the sleeping pads. Rab's new air mattress Ultrasphere 4.5 is "highly insulating, comfortable, lightweight, and inexpensive", and is still a godly mattress that is always "buy"

Last season, Rab Ionosphere 5 ( see review) brought us another shocking new product this season, this season, and Rab, a full-scale British outdoor brand that has achieved high performance that is hard to believe it was their first entry into the sleeping pad genre at an affordable price.

That's what we're reviewing Rab's new sleeping pad, Ultrasphere 4.5 . Although it is a lightweight mattress like a feather, it is not only light, but also excellent insulation and Rab's speciality in detail.

Thankfully, this time we are able to provide this site with the condition that you can freely review it. I was able to try staying in a tent with this mattress this season, so I'd like to review it.

Key Features of Rab Ultrasphere 4.5

The Rab Ultrasphere 4.5 is an all-season, air-injected sleeping pad that combines lightweight and compactness with high insulation. Though it weighs only 370 grams, TILT technology with a high insulation structure that uses heat reflectance provides a high R value (heat retention performance) that is year-round at 4.3. The 8cm thick, flat horizontal baffle structure, and quiet design that reduces friction when turning over, helping you sleep comfortably without feeling stressed even on uneven terrain. The thin two-way valve allows for short and easy injecting air using the included pump sack. Despite its high functionality, its amazing cost performance is still as attractive as ever.

Favorite points

• High insulation to cover the snowy season
• Lightweight and compact, which is hard to imagine due to its high insulation properties
• Enough thick
• Flat baffle structure with moderate unevenness
• Quietness
• The outer material is grip print that prevents sleeping bags and pillows from slipping
• Convenient 2-way valve system and dedicated pump sack
• Surprisingly low price for overall performance

Interesting points

• The back is slightly thin at 20D (it is TPU coating so it is sturdy than just 20D polyester).
• If I had to say, it would be difficult to open the cap when deflated

Main Specifications and ratings

Detailed review

Insulation, weight and size: "Weight vs. insulation performance" with excellent detachability due to its unique insulation structure

What will surprise everyone when they first picked up this mat is how light and compact it is. The main unit weighs 370 grams, and when packed, it is much more compact than a Nalgen bottle, making it so light and small that a few years ago you might have thought, "Are you thinking that it's a summer-only model?" The reduction in weight and storage size is not enough for hikers looking for tough adventures to benefit from.

However, the most important spec is the insulation (warmth; how hard a matt to lose heat), and it has a value of 4.3 in the global standard ASTM R-Value, which indicates the insulation of a mattress. Although this value is roughly not high enough for winter mountains only, it can be said to be a highly balanced value with high insulation and versatility that can be used throughout the year, including spring, summer, autumn and winter (snow mountains).

This high level of balance is achieved through heat-reflecting film using the proprietary technology " TILT (Thermo Ionic Lining Technology) Technology," which reflects the heat generated by your body inside the pad to minimize the loss of radiant heat, and an offset baffle structure that prevents the convection of warmed air. The diagram below shows the arrangement of each baffles inside the mat and the air flowing through the holes open in the baffle, but the arrangement makes it difficult for convection to occur because the holes are staggered and the holes cannot flow in a straight line.

By combining these two mechanisms, it is possible to efficiently trap heat inside while reducing weight and volume to the limit, allowing for the highest level of "warmness per weight (or storage size)" that is the highest.

Comfort: Exquisite sleeping comfort that combines basic flatness with subtle waves that are not easily slipped

Made for a wide range of mountain activities, from mountain bikepacking to alpine traversing to weeks of thru-hiking, the mat features a thin, lightweight recycled polyester front and back fabric of 20 denier, and is designed to keep this thinner and durable as possible with reinforced with a highly airtight TPU coating. It is certainly not so thin, but it does not seem to be fragile, as the pebbles will tear just by rubbing them. Although some care is required, there is a sense of security that is so good that it can be used in a tent with a floor.

The shape is basically a mummy shape with no corners and tapered towards the feet, but the toes are not that thin (photo below).

surface

Back side. The air outlet is located at the feet of this surface.

It is thick enough at 8cm, so even when sleeping on your side, your body will not only touch the ground, but you can rest assured that side sleepers will also be safe. You don't have to worry about the uneven terrain, and you can experience the luxurious sleeping experience, just like you're sleeping in a bed.

Ultrasphere 4.5 is a horizontal baffle structure with horizontal tubes lined up. Compared to the vertical baffle structure, this style has fewer bumps and flat surfaces, and even if the weight is concentrated on one point, the ups and downs are milder, so it allows you to stay more natural and comfortable than the vertical one, whether sitting or lying down.

Furthermore, the lateral baffle itself is gently wavy, so it is less likely to slip off, although it may be slightly less likely to slip off when you roll over.

And (as I realized this when I was using an Ionosphere 5), even though it uses metal film, the rustling noise remains the same as ever, and the sound is quiet and doesn't interfere with sleep.

As far as I went to review this time, I spent one night in a low mountain tent (at night temperatures around 3°C), but despite the fact that my back was hit directly by a quilted sleeping bag, I couldn't really feel the cold air from the ground. Of course, the way you feel it varies depending on your sleeping bag, but it seems like it can be used in a wide range of ways, such as combining it with your sleeping bag in the chilly season, or sleeping directly in the summer.

Storage and usability: Amazing compactness in this class

Ultrasphere 4.5 is an air-injected air mat. Of course, air must be injected into the product in order to use it. This is not uncommon with the high-end models these days, but in addition to injecting air directly through the mouth, the mat can be easily inflated using the included dedicated "Elephant Pump Sack (photo below)."

The air inlet is Ionosphere (photo below). The protrusions are relatively small, so it is flat against the mat surface, so it doesn't get in the way when sleeping or storing. It is not easily broken and is safe.

I personally like the large-capacity pump sack, and if you collect enough air, you can inject it to almost the maximum by simply blowing it in about 3-4 times.

Cost Performance: As dangerous as ever

The Rab Ultrasphere 4.5 an incredible performance that is unparalleled with excellent insulation and comfort, providing an incredible lightness and storage size without sacrificing excellent insulation and comfort , but what's more special about it is the price. Like last year's Ionosphere 5, we compared the main specifications and prices with three typical sleeping pad models with similar R values ​​(mummy air mattress with R values ​​around 4.5 to 5.0) (gold backgrounds are the highest value). Each model has its advantages, and the best model for you may differ depending on what you place your emphasis on, but the Ultlrasphere 4.5 stands out in terms of weight and storage size, and it is clear that the price is far superior to the competing models. Considering that the inferior parts are almost completely different, this high cost performance is not to be overlooked.

Comparison of major models of mummy air mats suitable for all seasons 2024

Summary: Recommended for people like this

Rab Ultrasphere 4.5 Regular Dark Pewter

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I was also quite surprised at last season's Ionospheare Ultrasphere 4.5 may have surpassed that. Despite the highly lightweight and compact design that Ionospheare The Ultrasphere 4.5 fits a wide range of activities, including speed-first hikers, climbers, alpinists and cycle tourists, and is a mattress that is recommended for anyone who doesn't want to compromise on comfort, weight and performance. On the other hand, there is another option for those who just need to be light, and who want comfort even if it's heavy. If you're thinking of getting a full-fledged air mattress that can be used for a long time, then this may be the year. Be sure to pick it up at the store and check it out.

Combined with the simultaneous release of "Mythic Ultra 120 Modular Sleeping Bag," this lightweight, comfortable sleeping system is now available at 700g under three seasons.

When combined with the company's lightest down sleeping bag, "Mythic Ultra 120 Modular," which was released at the same time by Rab, it completes a lightweight sleeping system that weighs less than 700 g, even at low temperatures of 0°C.

Of course, the Ultrasphere 4.5 is certainly a great solo sleeping pad, but if you're looking for a lightweight, uncompromising overall equipment, you might want to consider this option as well. By the way, we will also be posting a review on "Mythic Ultra 120 Modular" on this site at a later date, so please look forward to it.

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