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US Backpacking Sleeping Bag MT500 23°F - Polyester

Sale price: $60.00 Regular price: $89.99

This mummy bag is filled with our thickest wadding: guaranteed comfort! You'll love its 2 side zips with a double slider for optimal ventilation. It can also be twinned.

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Sale price: $60.00 Regular price: $89.99

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San Francisco, 735 Market St. Options

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Model: 8750218

Product Videos

Product Features

A photo of the US Backpacking Sleeping Bag MT500 23°F - Polyester in use
A photo of the US Backpacking Sleeping Bag MT500 23°F - Polyester in use

US Backpacking Sleeping Bag MT500 23°F - Polyester | Our designers, who are all trekking enthusiasts, designed this sleeping bag to sleep comfortably in a bivouac at temperatures above or equal to -5°C.

This mummy bag is filled with our thickest wadding: guaranteed comfort! You'll love its 2 side zips with a double slider for optimal ventilation. It can also be twinned.

Optimal temperature

Comfort temperature rating -5°C, limit temperature -11°C. Synthetic padding

Easy to transport

For size L. Weight: 2100g. Volume : 19.1 L. Stuff Bag

Sleeping comfort

Comfortable mummy shape. 2 x 3/4 zips with a double slider for ventilation.


Can be twinned with other models from the Forclaz MT500 range

Water repellent

Outer surface of the fabric is treated so that water runs off the surface

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Image Gallery

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US Backpacking Sleeping Bag MT500 23°F - Polyester, dark green Image 3 of 3

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Product Customer Reviews

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Very good product

Very good product

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Zipper is terrible

The sleeping bag is very comfortable and warm, but none of that matters if the sleeping bag can no longer be closed after two nights. No purchase recommendation!

Cover problem

Impossible to put back in its cover once unpacked. Bulk results in a bag. Not yet tested in real conditions.

Good investment

It is an excellent sleeping bag for what it proposes. Negative points: - the smallest size available is M. Too big for a height of 160cm, for example. There should be size S - as always, packing it in the transport bag is difficult, it takes time for those who don't have much experience

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Not Worthy.

Using this product since one month. It is not worthy as pr price. Specially discription given 5°c - -5°c. Seriously doesn't work in such conditions. If u planning to buy this to use in even 5°c u have to buy a blanket to use underneath. Not recommended for use above 10k ft. It's only 9°c and Im using blanket underneath. Specially the lower side is verry thin how can such product can save u from -5°c and u can see light passing through from inside of white side. Such a waste of money it cost more then 7k. If u buy 3k sleeping bag from local mrkt it'll be worth then buying this.

Sleeping bag

Does what it promises

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Tested at the limit

In mid-October I started climbing Kilimanjaro. During the five nights that you have to spend in the tent, the temperatures can drop to below -10 degrees, even in Africa. So I needed a sleeping bag that could keep up there... and I found it :o) At over 4,500 m you still need merino underwear. Otherwise, the MT500 kept what was promised. Great sleeping bag! ... and the summit climb was also successful. ;O)

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Conforms to the description

This product conforms to the description and I did not feel cold in the high mountains, no problem with storage alone and in less than a minute it was done, given the comments I think that some are not very good, only downside it is very but then very imposing in this cover otherwise perfect.


I used it in a 4-5 degree camping. I used a 2.7 r value mat and thin clothes and the night felt warm. Very comfortable and comfortable, I would definitely recommend it.

- Still no…

- Still no zip fastening in Decathlon sleeping bags. So it opens all the time! I point out to you that competitors have been doing this for a long time. + Beautiful dark green color. + Compressive cover. + 400G & in triple thickness, it swells very well. + 2 simple & effective tightenings. + Very thick and effective collar to insulate the opening. + Good value for money. + Realistic comfort temperature -5°. But only for a warm sleeper, and in the best conditions. + Does not stink of chemicals. My conclusion: I have been using it every day for 3 weeks, and I am satisfied with it. I warn you that it is huge. So I only carry it on the outside of my backpack.

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Use at 5°C…

Use at 5°C perfect I recommend the sleeping bag and no problem putting it back in its bag thanks to the DECATHLON recommendation!!!!!!

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I like

I used it in Malatya earthquake zone at -17. Good product

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Comfort -5°C? No !

In pants/sweater under the tent in the bag with a temperature of +5°C (refuge warden who gave it to us), and with mattress! Cold to the point of not being able to sleep... Fortunately I was leaving for a 2 day trek otherwise I would have had to cut it short! I'm going to use it for summer and buy a spring/fall bag elsewhere. Conclusion a very bulky sleeping bag for very approximate thermal coverage.

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not easy to fold…

not easy to fold up to put back in its cover

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Additional Product Information


Padding: 100.0% Polyester ; Main fabric: 100.0% Polyester ; Carry bag: 100.0% Polyester ; Lining: 100.0% Polyester

What is the temperature rating?

We display the comfort temperatures on all our sleeping bags, tested by an independent laboratory (AITEX) in compliance with European standard ISO 23537-1:2022. The comfort temperature rating is the lower limit at which the user in relaxed posture is generally in thermal equilibrium and feels neither too cold nor too hot (for a standard woman in normal conditions of use). Choose your sleeping bag according to this criterion.

What is the temperature rating (lower limit at which you feel comfortable)?

The comfort limit temperature is the temperature limit at which a person curled up in the sleeping bag is in general thermal equilibrium, neither too cold nor too hot (determined for a man in normal conditions of use).We recommend using an insulation mattress to optimise your thermal comfort.

An important clarification concerning the iso 23537-1 standard

In the context of this standard, the measurement protocol of a sleeping bag’s thermal protection uses a mattress with thermal resistance equal 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 therefore recommend you use an insulating mattress to optimise your thermal comfort.

Some advice to consider before you get into your bag

Dress simply (1 layer of clothing is enough). Warm-up your extremities: hats, gloves, socks, hand/feet warmers, rubdowns, etc. A flask of hot water can be used as a hot water bottle (as long as there's no chance of it accidentally opening!) Contract your muscles (70% of the energy consumed is converted into heat) but do it without moving as this could create a draught. Use a bag liner to optimise warmth and avoid washing your sleeping bag too frequently.


Mummy shape that is wide at the shoulders and more narrow at the feet to optimise thermal insulation (no heat loss) and compactness, while maintaining relative freedom of movement.Width at the shoulders 74 cm, height at the feet 36 cm in size L. 78/38 in XL, 70/34 in M

Weight and dimensions:

Size M: 2000 g, user up to 1.69m tall. Bag dimensions: L 44 cm Ø 22.5 cm. 17.5 litre volume.Size L: 2100 g, user from 1m to 70m tall. Bag dimensions: L 44 cm Ø 23.5 cm. 19.1 litre volume.Size XL: 2400 g, user from 1m to 2m tall. Bag dimensions: L 44 cm Ø 24.5 cm. Volume 20,7 L. Volume & dimensions can vary according to the pressure applied to the product.


Ergonomic hood with drawcord.Double collar for protection from the cold.A baffle along the zips prevents heat loss.Double-slider zips for optimal ventilation.The top of the sleeping bag can be opened with the two side zips.

Want to know more about the wadding?

We use 3 layer of 100% polyester wadding (70% recycled) of 115 g/sqm.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.


Can be twinned with all the Forclaz MT500 sleeping bag models.Can be twinned with the older models in the 2017 ”Ultralight” and 2018 ”Light” ranges.

Product testing

All our sleeping bags undergo mechanical tests that test the performance and resistance of the sleeping bag to guarantee better sleep and recuperation (thermal resistance, resistance to abrasion, comfort, etc). We also carry out many tests in the field, in real conditions.

Storage instructions

You can easily store your bag by stuffing it loosely into its cover, feet section first. To keep it fluffed up & ensure good thermal performance, remove from its cover, extend, store it in a dry place.



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For 40 years, Decathlon has delivered the best value in the retail sports industry by offering high-quality, sustainable and cost-effective products.

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