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Simond MT500 23°F Polyester Sleeping Bag
With its mummy shape, it is relatively light and compact to meet the needs of trekkers. The 3/4 length zip makes it easy to open.
Free shipping over $49
Free returns
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San Francisco, 735 Market St. Options
Select an available color and size to see options.
Product Features

Optimal temperature
Comfort temperature: -5°C, lower comfort limit: -10°C.Synthetic wadding
Lightweight
For size L. Weight: 1650 g.Volume: 16 L. Stuff Bag
Easy to use
3/4 length, anti-pinch zip.
Adjustable
Hood adjustable with elastic cord and drawstring
Water repellent
Surface-treated outer fabric (PFC-free) so the water slides off
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Product Customer Reviews
It maintains body temperature, does not make you sweat or feel overwhelmed, it is nice, I recommend it
👍🏻👍🏻
My experience with this sleeping bag on a February winter trek to Annapurna Base Camp was positive overall. It kept me comfortably warm despite the harsh conditions, although it did take up a significant amount of space and added some weight to my pack.
The product is very good, the only problem is the size is a bit big
I would like to point out that it is only for negative temperatures. It's an excellent sleeping bag, I haven't tested it exactly in negative temperatures, but in temperatures close to zero it works very well, just sleeping with a light layer. In case of temperatures above +5c you can sleep in a T-shirt. It's great, I highly recommend it.
I bought this Forclaz MT500 sleeping bag as an alternative to my sleeping bag, a more robust and less fragile model. After testing it at an altitude of 2,000 meters in temperatures around -6°C, I was pleasantly surprised: I wasn't cold at all! It was truly comfortable, allowing me to spend a warm and pleasant night. It's true that the bag is a little heavy and slightly bulky, but that didn't bother me. Personally, that's not a problem, because the main thing is that I slept comfortably and warm. This is a key criterion, and this bag fulfills this mission perfectly. Moreover, it's no bigger than my Frand Froid sleeping bag, which is a real plus in terms of practicality. Contrary to some reviews I'd seen on the website, I had no trouble putting the bag back in its stuff sack. There's no need to fold it perfectly; simply stuff it into the bag, and it can be stored away in seconds without any hassle. No need to worry about folding it; it's still a sleeping bag after all! In summary, I'm really satisfied with this purchase and highly recommend it to anyone looking for a sturdy, high-performance sleeping bag for cool to cold conditions.
A very good product, well priced and frankly very warm. Used it on a 3-day outing where there was morning frost, no problems. It packs down nicely and provides excellent protection. The downside is that you have to fold and compress it carefully to put it back in your bag! It's not easy the first few times, so don't be in a hurry to leave ;-).
Price performance
It can be said that the values in the comfort range are good, but in this case it varies from person to person in my opinion, the comfort value of this jumpsuit is ideal for 0 + 5 degrees, when I use it at minus degrees, it is inevitable to get frostbite locally, you should know that this jumpsuit will do the job for you up to 0 degrees, you cannot find a lower comfort level in synthetic jumpsuits, if you are going to camp at minus degrees, I think you should look at goose down jumpsuits, you will see a minimum of -15 at any high altitude in the winter, even if you stay in a tent with a stove, when the stove passes, it becomes the same value as the outside environment, the inside of the tent, that is, the jumpsuit, is of vital importance, make your choice consciously, this comfort value will do the job for you in Istanbul. A synthetic jumpsuit with a comfort value of -15 would be more guaranteed at least for winter. I wish it was an option for all conditions, but it is not.
The product is very light, the color is very nice, it keeps warm.
I didn't expect much for this price and was surprised that the sleeping bag maintained a comfortable temperature at -2° and thin sleeping clothes during the first test. But it doesn't go any lower without "help". In combination with a summer sleeping bag (Abisko Two Sewasion) I almost had a build-up of heat at -6°. The sleeping bag is very wide cut, so very comfortable and another sleeping bag fits easily in without it being tight. Therefore it is the perfect combination sleeping bag when it gets really cold. I would personally assume that you can sleep warmly at -8°C or lower in combination. (Unfortunately these temperatures are very rare here). But there is also one point for improvement: the clamp for adjusting the hood is very poorly shaped and you never know where to press. It should be replaced!
warm and comfortable but very bulky, bulky and heavy
I used the product while camping in the plateau at the end of January and the beginning of February. I had an insulated inflatable mat underneath me and I literally sweated when I stood there for too long. I ventilated it from time to time and did not feel cold from my feet to my head. It was over -7 degrees at midnight. It would have been better if the cover was a little more durable and compressible. Other than that, it is a great product.
I had to return it because it was too small and takes up a lot of space in my backpack, but other than that it's good quality! The only annoying downside is packing it back into the case.
Additional Product Information
Composition
Padding: 100.0% Polyester ; Lining: 100.0% Polyamide ; Main fabric: 100.0% Polyamide ; Carry bag: 100.0% Polyamide
What are the features of the mt500 -5°c sleeping bag?
Ergonomic hood with drawcord.Double collar to prevent heat from escaping. A baffle along the zip prevents heat loss.Double-slider zip for optimal ventilation.Inside pocket
What is the comfort rating?
We display the comfort temperatures on all of our sleeping bags, tested by an independent laboratory (AITEX) in compliance with International Standard ISO 23537-1:2022. The comfort temperature is the minimum temperature that an average person (woman, 25 years old, 60 kg, 1.60 m) is at ease, without feeling cold, in a relaxed position.Choose your sleeping bag according to this criterion.
What is the lower temperature limit?
The temperature limit is the minimum temperature at which an average person (man, 25 years old, 70 kg, 1.73 m) can sleep curled up without feeling significantly cold.And for information, the extreme temperature is the minimum temperature at which a person can survive (risk of hypothermia) for 6 hours.It is a measure of safety, and not of comfort.
Which mattress should i use this sleeping bag with?
The protocol for measuring the thermal performance of a sleeping bag is to use a mattress with a thermal resistance corresponding to an R-value of 4.8.This means that by using a less insulating mattress, the thermal performance of your sleeping bag will be lower.We recommend that you use an insulating mattress for better thermal comfort.
Weight and dimensions of the different sizes of mt500 -5°c sleeping bag
Size S: not available.Size M (users between 1.60 m and 1.69 m): 1500 g.Folded size: L 41 cm diam. 22 cm.Volume 15 L.Size L (users between 1.70 m and 1.84 m): 1650 g.Folded size: L 41 cm diam. 23 cm.Volume 16 L.Size XL (users between 1.85 m and 2 m) : 1810 g.Folded size: L 41 cm diam. 24 cm.Volume 18 L.Weight, volume and dimensions can vary by +/ -5% due to manufacturing tolerances.
How can i keep warm in the mt500 -5°c sleeping bag?
Dress simply (1 layer of clothing, ideally made from merino wool, is enough).Protect your extremities with a hat, gloves, socks and hand warmers if needed. Use a sleeping bag liner to optimise heat and avoid over-washing your sleeping bag Choose a mattress with good insulation (R-value> 3).And an extra tip: contract your muscles (70% of the energy consumed is converted into heat) but do it without moving as this could create a draught!
How to repair your mt500 -5°c sleeping bag
On a trek, you can snag a sleeping bag, it happens! The good news is that it can be repaired to prevent the tear from getting bigger or the synthetic fibres from escaping.To do this, we recommend that you use self-adhesive repair patches (ref: 8584596).If you don’t feel comfortable doing this yourself then a heat-bonded patching service is available at the workshop of your Decathlon store.
Do you want to know more about the wadding used in your mt500 -5°c sleeping bag?
We use 3 layers of overlapping wadding: - two 115 gr/m2, 100% polyester.- and one 150 gr/m2, 100% polyester.The wadding is made from silicone-coated spiral fibres that make it highly compressible and highly durable.Despite its low thickness, it has high insulation properties thanks to the air trapped inside, and remains lightweight. It retains its warmth even when wet.
How durable is fabric of the mt500 -5°c sleeping bag?
On the outside, it is made of 100% polyamide, 38 g/m², 20 denier. This fabric can withstand up to 20,000 abrasion cycles.Durability is calculated using the Martindale test (Standard 12 947-2). This test involves rubbing the bag material against another material to assess the product's abrasion resistance.The inner lining is made from a 100% polyamide fabric in 20 denier, weighing 35 g/m2.
Storage instructions
To keep your MT500 5°C sleeping bag fluffed up and retain its thermal performance, it’s best to store it loose out of its carry bag.
Origin
Imported

Simond MT500 23°F Polyester Sleeping Bag
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Heavy products return policy
If you return a product you will receive a refund for the purchase price plus any applicable sales taxes, less any non-refundable charges.
Decathlon will cover all shipping costs associated with your return except for items excluded from our return policy such as bikes, basketball hoops, snowboards, surfboards, tents, and other larger / heavier items.
Return costs for heavy products:
Weight Thresholds | Shipping within California | Shipping outside of California |
---|---|---|
> 9 lbs | $20.00 | $25.00 |
> 30 lbs | $50.00 | $65.00 |
> 100 lbs | $100.00 | $125.00 |
> 200 lbs | $200.00 | $230.00 |
If you return a product at any of our store locations, we will gladly help you find the best alternative product or refund you on the spot.
