131g (175cm)
150g (200cm)
175cm x 50cm x 1cm (175cm)
200cm x 50cm x 1cm (200cm)
Introduction
The World's Lightest Sleeping Pad
One of the world’s lightest sleeping pad made Made of XLPE foam, which has very high insulation properties and is extremely light, achieving less than one-third the weight of previous closed-cell mats.
The surface isn’t very durable and can chip with friction, so some care is required when handling . But if used with care, it is perhaps the lightest pad you will ever find.
Size
Three sizes to choose from
The UL Pad 15 is available in three sizes: 50 cm x 100 cm, 175 cm, and 200 cm. You can easily customize the size to suit your needs by cutting it with a utility knife.
For example, trimming 30 cm from a 200 cm pad results in a 170 cm x 50 cm full-body pad and a 30 cm x 50 cm extra piece. The smaller pad offers versatile utility: use it as a backpack back panel, a seat cushion during rest stops, or an additional layer to wrap around your waist on cold days.
*When cutting, use a ruler to hold the pad firmly in place and make a single, clean cut. Multiple cuts can result in uneven edges.
100cm（75g）
175cm（131g）
200cm（150g）
Product Story
A Blessing Born in the Snow
The UL Pad 15 was actually our very first product back in 2011.
When I and my wife, Yumiko were working on the prototype of a backpack before we officially launched the company, we were looking for a good quality core material that was as light as possible to use for the back padding and shoulder straps. However, few companies were willing to listen to us because nobody knew us.
That’s when we found a material which we thought was perfect. When we contacted the company selling it, the person in charge was a thru-hiker of the John Muir Trail, which we had also walked, and he was the only one who listened to us. Thanks to him we were able to test a variety of materials, one of which was XLPE foam, the material used in the UL Pad.
Experienced once in a decade heavy snowfall in Yakushima.
In the winter of that year, I went to Yakushima with a friend to test a prototype backpack. That day, it was snowing hard for the first time in 10 years on the island, so the hike didn’t go as initially planned and we had to bivouac in the snow.
It was so cold that I couldn’t believe we were in Yakushima. I was searching through my bag for something to keep me warm, and I noticed the XLPE foam that I had inserted in my backpack as a back pad. I put it on my back and it was unexpectedly warm, allowing me to sleep without worrying about the cold.
XLPE foam is extremely light and warm. Inflatable air pads and down pads for use in the snow are expensive and hard to come by, but this material is reasonably priced, and if it’s cold, it’s not too heavy to take two of them with you. In the old days you could cut off the ends of a closed cell pad and be happy that it was a bit lighter. With this material, the weight could be reduced to about 1/3 of the weight of sleeping pads that were previously considered lightweight. I knew I had to commercialize it as a sleeping pad right away.
As it turned out, XLPE foam was not a good core material for a backpack, but if I hadn’t been cold in the snow that day, I wouldn’t have decided to use it as a sleeping pad.
Even though it is not very durable because it’s so light, I’ve been using the same UL Pad 15 for over 5 years now. The edges are tattered and the torn parts are repaired with tape, but I like it this way.
Form and Function
Unmatched Lightness
We compared the weight of the UL Pad 15 with other popular sleeping pads as of June 1, 2024. Not only does it outperform inflatable and air mats, but it also offers a significant weight advantage over other closed-cell foam sleeping pads.
Lightness vs Durability
The UL Pad 15 is made from highly insulating XLPE foam.
XLPE foam is water-resistant thanks to its closed-cell structure, making it ideal for use on snow or wet ground. It’s also eco-friendly, as no chemical foaming agents are used in its production.
With ultralight gear, the trade-off is often durability, and the UL Pad 15 is no exception. It can tear under significant force, and friction may cause the surface to chip. However, even when damaged, its insulation performance remains unaffected. With a bit of care, this pad can be the ultimate ultralight sleeping pad!
Left: new
Right: 5 years of heavy use.
Lineup
The UL Pad series includes three types: UL Pad 15, UL Pad 15+, and the Minimalist Pad, each designed to suit different temperaturesn and seasons.
Note: Warmth and comfort levels vary by individual. Be sure to choose based on your personal experience and the conditions you plan to use it in.
Weight: 113g (100cm) / 198g(175cm) /
226g (200cm)
Thickness: 13mm
R-value: 2.0
Features: Yamatomichi’s core model. Featuring a textured surface that improves durability and cushioning compared to the UL Pad 15, along with a 30% increase in R-value. Performs well year-round.
Weight: 53g (One Size)
Thickness: 5mm
R-value: 0.7
Features: A super-lightweight, 0.5 cm thick sleeping pad with a textured surface for added durability. Ideal for minimalists, it can be used as an additional mat or wrapped around the stomach as an emergency layer in extreme cold.
UL Pad 15
Weight: 75g (100cm) / 131g (175cm) / 150g(200cm)
Thickness: 10mm
R-value: 1.4
Features: Yamatomichi’s original sleeping pad is less than half the weight of previous closed-cell pads, offering an excellent balance of R-value and weight. Suitable for use from spring to autumn.
Weight: 113g (100cm) / 198g(175cm) /
226g (200cm)
Thickness: 13mm
R-value: 2.0
Features: Yamatomichi’s core model. Featuring a textured surface that improves durability and cushioning compared to the UL Pad 15, along with a 30% increase in R-value. Performs well year-round.
Weight: 53g (One Size)
Thickness: 5mm
R-value: 0.7
Features: A super-lightweight, 0.5 cm thick sleeping pad with a textured surface for added durability. Ideal for minimalists, it can be used as an additional mat or wrapped around the stomach as an emergency layer in extreme cold.
UL Pad 15
Weight: 75g (100cm) / 131g (175cm) / 150g(200cm)
Thickness: 10mm
R-value: 1.4
Features: Yamatomichi’s original sleeping pad is less than half the weight of previous closed-cell pads, offering an excellent balance of R-value and weight. Suitable for use from spring to autumn.
Thickness and R-value
The R-value is a key indicator of warmth: the higher the number, the better the insulation. Cascade Designs, creators of the “ASTM F3340-18” standard and parent company of Therm-a-Rest, offer the following guidelines: an R-value of 1–2 is ideal for summer use, 2–4 works well for spring to autumn (three seasons), 4–6 is suited for winter conditions, and anything above 6 is recommended for high-altitude or extreme cold.*
For an in-depth look at sleeping pad types, R-values, and insulation performance, don’t miss our JOURNAL article Ranking Sleeping Pads by R-value. Let it be your go-to resource for finding the right pad for your adventures.
*Comfort temperatures varies by the individual.
Sleeping Pad Combinations
Stacking two UL Pad 15 pads, each with an R-value of 1.4, achieves the same warmth as a single pad with an R-value of 2.8. At just 75g (100cm)—less than half the weight of traditional closed-cell mats—our mats can be effectively combined to create a sleep system that redefines ultralight comfort and performance.
UL Pad 15+
Pairing the UL Pad 15 (100cm – 75g – R-value 1.4) with the UL Pad 15+ (100cm – 113g – R-value 2.0) creates a sleeping pad with a total R-value of 3.4, suitable for winter use, at just 188g. For comparison, the Therm-a-Rest ProLite Plus (R-value 3.2) weighs 450g (119cm), making the combination not only warmer but also significantly lighter.
UL Pad 15
Pairing two UL Pad 15 pads (100cm each) results in an R-value of 2.8 at a total weight of just 150g. This setup is not only lighter but also provides a higher R-value compared to models like the Therm-a-Rest Z Lite Sol S (R-value 2.0 – 290g), a leading model among closed-cell mats.
Minimalist Pad
Pairing the UL Pad 15 (100cm – 75g – R-value 1.4) with the Minimalist Pad (100cm – 53g – R-value 0.7) results in a lightweight sleeping pad with a combined R-value of 2.1 at just 166g. For comparison, the Therm-a-Rest Z Lite Sol S (R-value 2.0 – 120cm) weighs 290g, making this setup significantly lighter. By overlapping the two pads so they stack around two-thirds of their length, you create a full-length sleeping system with extra warmth around your hips, though your feet may feel slightly chilly.
The Minimalist Pad, also used as a back panel in MINI/MINI2 packs, folds compactly for easy storage.
NeoAir UberLite
Pairing a lightweight air mat with the UL Pad 15 provides both added warmth and protection against *punctures. The Therm-a-Rest NeoAir UberLite R (183cm – 250g – R-value 1.7), one of the lightest air mats available, combined with the UL Pad 15 (100cm – 75g – R-value 1.4) achieves a total R-value of 3.1 at just 325g. This combination offers winter-ready insulation while maintaining the weight of a typical three-season mat.
*While the closed-cell foam pad helps prevent punctures, using it directly on the ground can trap twigs and debris, which can be a potential cause for punctures to your air mat when stacked.
NeoAir X-Lite NXT
By placing the 175cm version of the UL Pad 15 (131g) under the highly insulating Therm-a-Rest NeoAir X-Lite NXT RS (R-value 4.5, 326g), you can achieve a system with an R-value of 5.9 and a total weight of 457g. This setup provides both superior insulation and lightweight performance, making it a high-spec system suitable for use even in severe winter conditions, outperforming many insulated air mats.
Instructions
Please Note
Due to its ultra-light weight, please be careful that the pad is not blown away.
- To avoid unnecessary damage, please handle with care and choose a flat surface when sleeping. Avoid rocks and sharp surfaces when possible.
- The material is anti-slippery, so it is easy to apply excessive force when using it as a frame for a backpack. Handle with care.
- If you pull or push it too hard, it is likely to get damaged.
- Scratches and signs of use will remain on the surface of the material.
- Please consider using this pad in combination with other pads (layering) in snowy mountains.
- Lay it inside your sleeping bag for extra warmth.
Care Instructions
Care Instruction Page
Visit our dedicated Care Instructions page for detailed guidance on maintaining your product. Proper care ensures extended functionality and helps you get the most out of your purchase.
Payment
- We only accept payment by credit card. We currently do not accept payment via bank transfer from overseas accounts.
- We accept the following Credit Cards: Visa, Master, American Express, and JCB.
- To download your receipt, please click the link included in the Dispatch Notice, which we will send by email as soon as the items are dispatched.
Delivery
- Order Confirmation will be sent after the order.
- The items will be dispatched within 3 days after the payment is confirmed.
- The dispatch notice will be sent by email as soon as the items are dispatched.
- The delivery may be delayed by unforeseeable reasons such as natural disasters and other logistics issues. We appreciate your patience and understanding.
- We cannot ship multiple orders in one package due to how our delivery system is currently set up.
- We will ship to regions in North America, Oceania, and Europe (excluding Russia) via DHL. For regions in Asia, the Middle East, Central and South America, Africa, and Russia, we use EMS (International Express Mail Service) for shipping.
- Shipping fees and delivery times vary depending on the shipping destination as well as the size and weight of the items.