Specifications
* Model # MR27
* Capacity: 1 person
* Weight: 650 g / 22 oz.
* Length: 235 cm / 92.5"
* Width: 70 cm / 27.5" tapering to 60 cm / 23.6"
* Head Height: 30 cm / 11.8"
* Colour: Olive
* Floor Fabric: PU Coated Taffeta Laminated Nylon Waterproof Bathtub Base, 10,000mm Hydrostatic Head
* Top Fabric: 3 Layer highly breathable 40D Exchange Lite eVent® Fabric, 10,000mm Hydrostatic Head
* Moisture Vapour Transfer Rate (MVTR): 15,000 - 25,000g/m²/24hr
* Resistance to Evaporative Heat Transfer (RET): 3-4
* Water Column: > 30 metres; waterproof at 92 km/h

About the Rab® Ascent Bivvy Bag
The Rab® Ascent Diamond Bivvy Bag is a 1 person eVent® waterproof fabric bivi with wide sleeping bag profile design and removable mesh zip door. A fantastic design that is perfect for alpine climbing or wild nights on the fells. Fully waterproof and breathable eVent® ensures a comfortable nights sleep even in the rain. The Rab® Ascent combines a wide sleeping bag profile with a waterproof eVent fabric construction for impressive weather protection and comfort. Developed to ensure that you remain warm and comfortable when sleeping outside, even in poor conditions, this weatherproof bivi balances water protection with breathability for a restful night’s sleep.

This lightweight bivi shelter is completely waterproof and highly breathable thanks to the eVent® Exchange Lite fabric, so you can now have a fully protected yet very light bivi shelter.  The internal mesh panel on the door helps to keep the midges and flies out and can be removed if you are absolutely fanatical about weight.  The Rab® Ascent is nice and roomy allowing for taller users up to about 6’2” and a small pack inside.  The box wall sides do increase the sense of space and allow your sleeping bag to loft naturally maximising its warmth.

The use of Exchange Lite eVent® fabric on the upper has reduced the bulk and weight considerably. There is a 10,000mm hydrostatic head PU laminated nylo waterproof base, however a much needed removable mosquito/midge netting has been added around the mouth of the bag, along with a supporting cord to allow the mouth to be kept open with an appropriate support.

So the result is a 650 g bag which is only slightly bulkier than a Rab® Survival Zone, but more durable and breathable. However with the addition of the netting, it does mean that (a) it can be used when the bugs are out, and (b) it'll keep the slugs out of your hair! A good length at 235 cm x 70 cm width with a gusset of 30 cm it is suitable for most people with a sleeping mat and a 3 season bag up to around 6'2". Ideal for general walking, bushcrafting, mountain climbing and lightweight quick ascents.

Exchange Lite™ eVent® fabric provides the ultimate in single wall breathability. The eVent fabric is also wind and waterproof. 10,000mm laminated lightweight ripstop nylon waterproof bathtub base keeps you dry. One innovative “donut” tie in point on top allow you to sleep securely tied into your anchor.

Features
* Wide profile allows use of large sleeping bag
* Zipped head entry with removable no-see-um mesh zip door panel
* Webbing loop to hold entrance open
* End zip entrance
* Glow in the dark zip pullers
* Side walls help maximise sleeping bag loft
* Supplied in waterproof roll-top stuff sack
* Opening: U-shaped zip opening with removable mosquito-net/mesh zip door panel
* Stormproof: Yes
* Seasons: 3 - 4 seasons
* Seam Taped: Yes
* Perfect for: Mountaineering, alpine, trekking, paragliding and general outdoor use

About eVent® Fabric
eVent® is the most breathable direct venting waterproof fabric on the market today. eVent® has allowed Rab® to produce a range of fully protective mountaineering shell clothing that maintain comfort levels previously only dreamed of. eVent Waterproof Fabrics use Direct Venting Technology -  a proprietary and patented waterproof membrane allows millions of tiny pores to breathe at their full potential. Sweat vents directly to the outside of the fabric in one easy step.

The "Direct Venting" and "Dry System" - Most common waterproof/breathable technologies do not literally "breathe". Instead they move sweat in two slow steps by a process of diffusion through a Polyurethane (PU) layer. First sweat is condensed and absorbed into the PU layer on the inside of the fabric. Because PU absorbs and retains sweat, the inside of the fabric becomes wet. Then, body heat begins to push that dampness through to the outside of the fabric where it can finally evaporate - a very inefficient process.

eVent® fabrics get their unique properties from a proprietary and patented waterproof membrane. Its unique composition allows millions of tiny pores to breathe at their full potential. Sweat vents directly to the outside of the fabric in one easy step. We call this Direct Venting™ Technology. Its genius is hidden in its simplicity. eVent fabrics simply let the sweat out.

All eVent® fabrics protect you from the wind, and all are designed to add another level of fabric protection from the elements - without compromising comfort and breathability through the unique Direct Venting™ Technology.

But how can we measure 'breathability'? eVent fabrics feature exceptionally low "Water Vapor Resistance" (RET) and the "Moisture Vapor Transmission Rates" (MVTR) are very high in laboratory tests. But, do you run or climb in the lab? Where it really matters is out there in the Mountains. Out there it's a black and white world: you're either wet or dry. It's that simple! eVent® fabrics let the sweat out.™ eVent® is the most breathable direct venting waterproof fabric on the market.

About Rab®

When Rab Carrington started a small company in 1981 Sheffield he was relying on his extensive experience gained on bold, lightweight first ascents to design and manufacture down clothing and sleeping bags of the highest quality. This equipment had to meet the needs of a new breed of lightweight alpinist using techniques pioneered by Rab himself. This equipment had to be designed 'for the most extreme conditions in the world'.

To this day that ethos lives on. The range of product offered may have expanded dramatically but the core values of quality and performance live on. The Rab® range now encompasses all layers from the skin out and makes best use of our close relationship with all our fabric and component suppliers to produce lighter, more breathable, durable and comfortable clothing allowing mountaineers to push their limits in the most hostile of environments.

Heritage

Rab's legacy continues, the passion, thinking and driving force behind the Rab® brand remains to be designing and producing equipment and clothing 'for the most extreme conditions in the world'. The Rab® brand is renowned for producing outstanding quality clothing and sleeping bags, suitable for extreme cold environments and high altitude mountaineering.

When Rab Carrington started making sleeping bags in Patagonia over 30 years ago, he did so to pass time and earn a few bob while he was waiting for customs to release his climbing kit. A talented climber, Rab spent much of the 1970s on ground breaking expeditions around the world and in doing so gained the best education possible to understand what climbers needed from their kit.

In 1968 in the Dolomites when everybody else was climbing in mountaineering boots, Rab used rock boots on routes such as the Phillip-Flamm and the Tre Cime. It is this approach to climbing that enabled Rab to design performance sleeping bags and down clothing. By first deciding what functions the gear needed to achieve and then designing for that purpose.

He combined his knowledge of the mountains with the skills he had learnt in South America and set up shop at home in Sheffield, UK. Rab made kit for climbers, by climbers and in the mid 1980s he became the first manufacturer in the world to use Pertex® in the production of sleeping bags and down jackets.

His legacy continues with Rab®, a group of people dedicated to making products for the most extreme conditions in the world. Their passion for the outdoors, their long standing partnerships with performance material suppliers and Rab®’s pioneering ethos have allowed them to continue to push these limits. The original ethos of Rab® remains core to current product development; a strong focus on using functional designs and high quality fabrics to produce premium gear for mountaineering and polar travel.

Environment

Environmental impact and sustainability are issues of great concern to the world today, and something Rab® take very seriously at Rab®. However, change doesn’t happen overnight and Rab® see improving our Environmental impact and sustainability as a continuing journey and not as a ‘destination’ to be arrived at.

The Rab® design team are all extremely eco aware and keen to instil this in their practices. They aim to make changes where possible that lessen the environmental impact of their products but that don’t compromise on performance. It is critical for the Rab® brand that they live up to their reputation for providing a durable kit and they are currently putting lots of effort into ensuring the best ways of balancing longevity, sustainability and affordability.

Rab® is renowned for producing clothing and equipment that not only works but lasts a long time. Rab® sleeping bags and clothing are known to last up to 25, even 30 years old and owners can’t bear to part with. Rab® provide a care and repair service and can even re-fill/condition some clothing and most sleeping bags.

None of this is simple and Rab® are adamant that they want to continue to improve.  More transparency is the key and they are working on this and are very aware of their responsibilities. Certainly there are no clear cut answers and they are keen not to make sweeping statements that they can’t back up. Rab® are not fearful of transparency but many people are very quick to criticise. Therefore, getting things right first time is really important as Rab® endeavour to lessen the environmental impact of their products.

Rab® are working very closely with suppliers, factories, carriers, and in both the UK and the USA offices to decrease the environmental impact of everything they do at Rab®. They are all active outdoor enthusiasts and they care about the environment and people that they share the outdoors with.