The Flame Fm4 from Sea to Summit is the streamlined, lightweight and high-performance sleeping bag designed for colder conditions.
This model has an expedition mummy bag size to give you extra space to move, and is narrower at the shoulders and wider at the hips for a women’s specific fit. The shell and lining are made from ultralight nylon to keep the packed size and weight down and is easy to access via the full zip with two sliders. This bag is filled with RDS certified 850+ Loft premium goose down that also has an ULTRA-DRY water-repellent treatment to protect it from condensation and external moisture.
The full box baffle construction reduces cold spots, while the vertical baffles on the chest prevent the down from moving around as you sleep. This bag provides a -10°C comfort rating and a -17°C lower limit, so it's suitable for use in hard alpine environments and colder climates.
To minimise heat loss, there’s a zipper draft tube, as well as a hood and front neck and backdraft collar. For maximum warmth on a lightweight expedition, the Flame Fm4 Sleeping Bag from Sea to Summit is the ultimate sleeping solution.
-10°C comfort rating, -17°C lower limit
Expedition mummy bag sizing provides extra space
RDS certified 850+ Loft premium goose down
ULTRA-DRY water repellent treatment on the down protects it from moisture
10D nylon shell and 7D lining for minimal weight and packed size
Light gauge #3 YKK ½ zip with two sliders for access and ventilation
Wider at the hip and narrower at the shoulder with extra down overall
Compression bag and storage cell
Full box baffle construction help reduce cold spots
Vertical baffles on the chest prevent the down moving
Zipper draft tube, hood and front neck and backdraft collar to minimise heat loss
Does the height of 39cm refer to when the sleeping bag is compressed?
Anne - Torquay, QLD(8 months ago)
G'day Anne,
No, it doesnt - it refers to the size of the compression sack itself. It's hard for us to provide compressed specs. 5 different people could get 5 different compressed dimensions depending on how the bag is stuff and how strong you are, etc The compression sack is roughly a 8L size, and I reckon you could get the bag down to around half the stuffed size.
Lauren - Snowys(7 months ago)
Is this a good weight for hiking?1 answer
How does this bag compare? We are looking for warm bag for hiking in Tasmania and Victoria in winter. Does it compare well in terms of weight to warmth? Less than 1kg for this warmth seems good to me …
Emma - Preston, VIC(1 year ago)
G'day Emma,
Yes, this is a great weight for hiking and one of our warmest and lightest sleeping bags with a comfort rating of −10 °C that should keep you toasty in cold Victorian and Tasmanian winters. You can also add a sleeping bag liner to add some extra insulation like the Thermolite Reactor Extreme Liner. This is a great quality option for winter hiking that is lightweight, packs down small, warm and insulating.
Kaya - Snowys(1 year ago)
Warmth rating1 answer
On my last extended hiking trip (autumn - winter 2022), I used a quilt rated -7°C. The temperature only would only reach 0°C on the coldest nights but I would need to be rugged up with every single one of my clothes to hope falling asleep and make it through the night. I'm a cold sleeper and I know that quilts can get drafty but didn't expect to feel so cold. Now, I'm looking at replacing my quilt with the Flam IV. I hike from autumn to spring but never in alpine or snow conditions. What bag (III or IV) would you recommend for the most versatile use of the bag? Are the ratings realistic, even for cold sleepers? I'm fearing the IV might be overkill... Thanks.
Lilly - Adelaide, SA (2 years ago)
G'day Lilly,
Quilt comfort temps are just a best guess - they can't be physically EN tested like sleeping bags. It's quite likely that if you were in a -7ºc sleeping bag you might have had a different experience. Having said that though, the general rule of thumb is to go with a comfort temp of 5ºc colder than the coldest temp you expect to be in, taking that down to 10ºc colder if you are a cold sleeper. This is to account for/and offset all the variables that can affect how warm you sleep. With that in mind, if you are in 0ºc temps, a -10ºc bag would be ideal. The other factor to consider is the R-Value of your sleeping mat. If your mat has an R-Value less than 4, your sleeping bag or quilt won't perform to the advertised specs. Bags with natural insulation such as down, have a greater application of use over a larger range of temps. A -10 down bag can still be used year-round, especially when you have the ability to fully unzip and use as a blanket. As the Flame series is ultralight, it cant be fully unzipped, so it will have slightly less flexibility.
I'd say for versatility it might be worth considering the Flame 3, and taking your quilt with you as an extra on trips where you're expecting super cold nights. Layering an additional quilt over your sleeping bag to extend the comfort rating is a super common practice. It allows you to have flexibility with your sleep systems year round, with the option to take either on their own, or both when you're needing extra insulation.
Hope that helps with your decision.
Lauren - Snowys(2 years ago)
Can this bag zip together with another S2S bag1 answer
We sleep as a couple and looking for the lightest 2 bag combo with temp rating to around 0 degrees
Ken - Rangeville(4 years ago)
G'day Ken,
The Flame sleeping bag can't be zipped to another bag, they've been designed to be as lightweight and compact as possible, so they're not able to be zipped to another bag. The Traveller TR2 might suit your needs, you can zip them to each other. Otherwise, the Trek TK2 and Journey JO1 have the option to zip together and should suit your temperature needs.
Leece - Snowys(4 years ago)
I'm 160cm tall and have size 10 feet. Should I buy a regular spark 4 or flame 4 sleeping bag? 41 answer
I feel the cold, so was originally looking at the flame 4. I am looking for a bag that is lightweight . I weight around 60kg. I'm worried that because I have big feet, the flame regular will be tight around my feet. Could you please give me some advice?
kerrie - karnup(5 years ago)
G'day Kerrie,
The regular length is designed for maximum user heights of 170cm, so you should be fine in the regular length. I'm 165cm and also have US10 feet and find the regular length a good size, with plenty of foot room. The Flame Fm4 will give you a slightly warmer temperature rating for the same weight bag, due to the smaller bag size. We'd generally recommend going for a women's bag as it will give you a little more hip-width which can be handy.