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Women's Ultralight Self-Inflating Sleeping Mat


$89.95 – $99.95

Sleeping Bag Temperature Ratings Explained

The EN Rating scale is a scientific test to determine the warmth of a sleeping bag. The test produces a Lower rating (for male sleepers) and a Comfort rating (for female sleepers). Both are listed in the features table on the product page.

A unisex sleeping bag with a Lower limit of 23ºF means a man should be comfortable down to air temperatures of 23ºF. The same bag will also have a Comfort limit, in the realm of 32°F, so a woman would be comfortable down to an air temperature of 32ºF. These ratings require a sleeping mat with an R-Value appropriate for expected ground temperatures – without this, the sleeping bag itself is unlikely to keep the sleeper warm enough.

A variety of factors impact sleeping bag warmth - the above temperatures are merely guidelines, not guarantees. It’s important to think of a sleeping bag, an appropriately insulating sleeping pad and a liner as a sleep system. For example - if you plan on sleeping in nighttime air temperatures of 27ºF / -3°C, choose a bag with a gender-appropriate rating of 23°F / -5°C, plus a sleeping mat with an R-Value of 2.5 to 3, and consider a Reactor thermal liner.


The Women’s Delta Core-V™ concept is simple: remove enough foam to cut down weight, leave enough foam to ensure comfort and warmth. The Women’s UltraLight Self-Inflating Sleeping Mat is constructed with Comfort Warmth Zones in the hip foot and torso areas to provide extra support and insulation for the woman backpacker who wants to keep her load light.

Silicone prints on the upper surface prevent your sleeping bag slipping, and the flip-over multi-function valve makes rolling up the self-inflating mat really easy.

Is this Self-Inflating Sleeping Mat…?

  • Suitable for backpacking? Yes. The Regular brings a mere 19 ozs / 545g to the scales and packs down to 5.25” x 10.75” / 13.5 x 27.5 cm. If you would like a sleeping mat that is even smaller and lighter, try the Women's Ultralight Insulated air sleeping mat.

  • Comfortable on rough ground? Perhaps. The foam core is 1” / 2.5cm thick, which offers a reasonable level of comfort. If you would like more support, you may care to look at the Women's Ultralight Insulated or Women’s Ether Light XT Insulated.

  • Warm enough for three seasons? Yes. This self-inflating mat has a tested R-Value of 2.9 which is warm enough for sleeping from late Spring to early Fall (we would think of this as 2.5 seasons).


Best Use

  • Ultralight Backpacking

Comfort & Support

  • Comfort Warmth Zones in the hip and foot area to provide extra support and insulation where women need it most.

Women's Specific Sleeping Mat Shape

  • Narrower in the shoulders, wider in the hips and knees. Offers greater comfort no matter what position you sleep in, and perfectly matches our Women's Sleeping Bags.


  • R-Value of 2.9 is fine for Spring to Fall backpacking
  • Women’s Delta Core-V™ technology means extra comfort and insulation for hips and feet, in a very light and packable self-inflating mat.
  • Silicone prints prevent your sleeping bag slipping.
  • Patent-pending multi-function valve twists over to allow the self-inflating mat to be rolled tightly without fighting re-inflation as you go.

Technical Features

SI Multi-Function Valve

We have literally put a new twist on our very successful multi-function valve so it specifically addresses the inherent characteristic of self-inflating mats - that is, the problem of the foam trying to re-inflate as you're packing up. We've engineered the "one-way" inflation valve to be reversed and used to prevent the mat from drawing air back in. This allows you to roll the mat up as small as possible without fighting re-inflation as you go. This patent-pending valve design has the same slim profile, faster inflation than traditional screw valves, easy pressure fine tuning, and super fast deflation rate as our air mattresses and pillows.

Pillow Lock™ System

The Pillow Lock™ System comprises of self-adhesive hook-and-loop patches which are supplied with all Sea to Summit sleeping mats (as of Spring 2019),

Attached to your sleeping mat, these patches secure your pillow and prevent it slipping – yet they will not snag on clothing or other lightweight fabrics.

All Sea to Summit Pillows (as of Spring 2019) are compatible with this system. Existing pillows can be made Pillow Lock™ compatible by adding an Aeros Pillow Case.

Women's Delta Core-V­™

The Women’s Delta Core-V™ system uses a revised pattern of Delta-shaped vertical cores to leave foam intact in the hip, foot and torso areas to create extra-comfort / extra warmth zones.

The coring technology results in a smaller packed size and lighter weight than conventional self-inflating mats while providing extra support and insulation where women need it most.

The Women’s Delta Core-V™ technique is used in our Women’s UltraLight SI models.

Tech Specs

Product Details

Best Use
Backpacking, bike touring
Comes With
Stuff Sack, Repair Kit, PillowLock™
30D Woven polyester with an anti-slip print
Women’s Delta Core-V technology
Season Rating
2.5 Season
Multi-function valve that prevents re-inflation as you roll the self-inflating mat.
1 in / 2.5cm
67 x 21 in / 170 x 53 cm
5.25 x 10.75 in / 13 x 27 cm
1 in / 2.5 cm
19.2 oz / 545 g
72 x 23 in / 183 x 58 cm
5.5 x 12 in / 13.5 x 30 cm
1 in / 2.5 cm
22.8 oz / 645 g

Customer Reviews

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