In the compression bag

Robens Icefall Pro 600 with MicroThermo Ball - Finally, a replacement for Down?

Robens Icefall Pro 600 with MicroThermo Ball

The Robens Icefall Pro 600 is a warm sleeping bag with the new MicroThermo Ball insulation - a potential replacement for down.

Review Score

Our Score: 9.2/10

We've given the Robens Icefall Pro 600 with MicroThermo Ball the Thumbs Up award.

GOWTK Thumbs Up Award
Value for MoneyQualityComfortInsulationPracticality

The good

  • A very warm sleeping bag.
  • It packs down well and lofts out when unpacked.
  • Comfortable; it's a mummy bag but with plenty of room.
  • Extra pull-cords and baffles to help keep your body heat in.
  • Not using down.
  • Looks well made.

The not so good

  • A bit more pricey than most family camping bags, which is to be expected for high-end technical camping gear.

This was a hands-on product review. The product was supplied to us to test and conduct the review.

Price Guide

Robens Icefall Pro 600 with MicroThermo Ball has a recommended retail price of £259.99.

The best price we've found so far is £137.95. That's £122.04 off the RRP of £259.99.

Robens Icefall Pro 600 with MicroThermo Ball Videos

YouTube Video Thumbnail

Robens Icefall Pro 600 with MicroThermo Ball Photos

In the compression bag

In the compression bag

Temparture Ratings

Temparture Ratings

Zip Insulation

Zip Insulation

Central Zip

Central Zip

Hood Pull Cord

Hood Pull Cord

Internal Pull-Cord

Internal Pull-Cord

Mummy Hood

Mummy Hood

In mesh bag

In mesh bag

Robens Icefall Pro 600

Robens Icefall Pro 600

Robens Icefall Pro 600

Robens Icefall Pro 600

Our Review

YouTube Video Thumbnail

New technologies keep getting better.

Some fantastic synthetic fillings are available; the latest is the new MicroThermo Ball filling. An artificial filling that has some of the good properties of down. But why is down so suitable for sleeping bags?

Benefits of Down Sleeping Bags

Down is the fluffy under feathers, typically from ducks or geese. Nature has evolved these feathers into fantastic insulators by trapping tiny air pockets.

And no matter how much you squash the features, they tend to spring back.

This makes them great for sleeping bags:

  • You get well-insulated sleeping bags using less material.
  • The sleeping bags can be squashed down very small, making them ideal for backpacks.
  • They last a long time as they keep springing back, despite being repeatedly squashed into a sleeping bag stuff sack.

Unfortunately, manufactured materials don't squash down as well. You tend to need more synthetic material than down. That means sleeping bags with synthetic material are larger and heavier.

Down isn't all wonderful, though.

It no longer insulates well if it gets wet, although many down features are treated with waterproofing these days.

Another issue is that down must be harvested for geese or ducks.  Wherever you stand on that ethics, there is one indisputable fact: it makes down very expensive.

It may also be a problem for anyone with allergies.

MicroThermo Ball

The filling in the Robens Icefall Pro 600 is the new MicroThermo Ball synthetic material.

Unlike previously manufactured fillings, the MicroThermo Ball springs back.

You can feel it if you squeeze the material between your fingers: it fills back out, like down.

And what's more, unlike down, it is naturally waterproof. And it's non-allergenic.

The result: a warm sleeping bag that insulates very well and in a much smaller pack size than other equivalent synthetic-filled sleeping bags.

Robens Icefall Pro 600 Review

Robens sent me a review sample of this sleeping bag to try out.

Robens Icefall Pro 600

The Robens Icefall Pro 600 with MicroThermo Ball insulation.

While you can get slightly smaller packs with some down sleeping bags, the Robens Icefall Pro 600 bag comes in a size that will easily fit in a bottom of a backpack.

In the compression bag

This is the sleeping bag in its compression bag, which measures around 37 cm long by 17 cm wide.

The Robens Icefall Pro 600 Temperature Ratings

Robens class this Icefall Pro 600 as a 2-3 Season sleeping bag, but it should keep you warm when the needle drops below freezing.

To me, this feels like a four-season sleeping bag. Both in looks with the amount of insulation and when using it. It's pretty warm :-)

After getting the sleeping bag out of the stuff sack, the bag filled out straightaway. I was very impressed with how such a large insulated bag could fit in such a small pack.

Another feature of this sleeping bag is the central zip instead of running down the side.

This works very well and makes it easy to sit up in your sleeping bag with the zip slightly open to free your arms, but keep the rest of the sleeping bag in place. That is not easy to do with a side-zip sleeping bag.

Central zip on the sleeping bag

The central zip has useful toggles on, making them easy to grab in the dark.

The zip is covered with two giant insulated baffles so you won't lose much heat.

Zip Insulation

Baffles of material cover either side of the zip to reduce insulation 'leaking' out where the zip is.

The sleeping bag is mummy-style with a hood. In addition to the expected drawstring around the hood, there is another inside the bag to pull insulation around your shoulders to help keep more of your body heat inside the bag.

Here's the insulated mummy hood on the Robens Icefall Pro 600. Notice the baffle at the back to help keep your body heat in the bag.

There is an additional drawstring around the waist.

A pullcord inside the sleeping bag that you adjust to help keep more heat in.

The feet area is a box section with added insulation, so your feet won't feel cramped or cold.

As well as the compression sack, the sleeping bag has a mesh sack. This is for storing the bag uncompressed at home.

This is the sleeping bag in its mesh storage bag. This is a bag to keep it in at home, allowing the filling to be kept uncompressed.


I found this a warm sleeping bag for a 2-3 season bag.

The quality was excellent, and it packs down to a reasonable size for such a well-insulated bag.

I will be using this bag a lot more, so if I find any issues, I'll update things here. But for now, this gets the thumbs up.

Thumbs Up


AttributeRobens Icefall Pro 600 with MicroThermo Ball
Best Price£137.95
Product InfoBrand Web Page
Width (cm)80
Length (cm)220
Weight (kg)1.075
Pack Size (cm)37 x 17
Year Introduced2021
Season2 Season, 3 Season
Comfort Temperature (°C)6C
Extreme Temperature (°C)-14C
Limit Temperature (°C)-1C