Mont Bell Insulation - Quick
Test

UL Down Inner Jacket
|
Price:
£99.99
|
|
Weight: 203 grammes (men's
medium)
|
|
Features
Ultraminimalist down-filled jacket using 800 fill-power
hypoallergenic goose down, 15-denier Ballistic Airlight
hollowfibre nylon shell, single quilt construction, DWR
finish, elastic cuffs, press-stud main opening closure (no
zip), hand warmer pockets, stuff sac included.
|

UL Thermawrap Jacket
|
Price:
£99.99
|
|
Weight: 248 grammes (men's
medium)
|
|
Features
Ultraminimalist synthetic-filled jacket using Exceloft
synthetic insulation, 15-denier Ballistic Airlight
hollowfibre nylon shell, fleece-lined collar, elastic hem
and cuffs, two hand-warmer pockets.
|
What's It For? New to the UK, Mont Bell is big in its home
market of Japan and not afraid of taking things to their logical
conclusion. Their UL series is intended simply to be as light as
possible. Both the synthetic and down jackets we've been using are
aimed at lightweight backpackers who want decent insulation that's
takes up minimal space and barely troubles the scales.
The down version is intended for cold, dry conditions where the
risk of water-logged insulation is minimal, while the synthetic
version is more suited to damper climes and less affected by
moisture.
The Techy Bits The key to both jackets is a super-lightweight
15-denier nylon shell material called Ballistic Airlight. It's made
from hollow fibres and weighs just over an ounce per square metre.
Mont Bell says that despite its filmy feel, it's actually twice as
tough as some materials weighing twice as much.
The down version has super high lofting 800 fill-power goose down
fill in a quilted, stitch-through construction to save weight. And, a
real statement this, uses a press-stud fastening instead of main zip
to save weight - below.

The synthetic Thermawrap version uses a synthetic fill called
Exceloft and has a normal zip along with a microfleece-lined collar.
And that's about it, told you it was simple.
How It Works Both these jackets are incredibly light. To put
them in perspective, a Rab Generator using lightweight Primaloft,
weighs 330 grammes compared to 203 grammes and 248 grammes for the
Mont Bell tops. They pack down small as well. We lost the stuffsacs
and resorted to stowing them in their own pockets, but pack size is
still impressively small.
The down version is significantly warmer than its synthetic
cousin. It may feel flimsy, almost as if it's made from air, but we
reckon the combination of down and windproof outer means its around
as warm as a typical mid-weight fleece but with added wind
resistance.
The press-stud fastening - no main zip - saves weight, but means
the jacket is strictly for static use, preferably in a sheltered
environment where there's no wind to penetrate the front opening.
Think hunkered down in a tent, sitting in a Himalayan trekking lodge
or in an adventure race campsite.
That's great in cold, dry conditions. However, while it does have
a water-repellant finish, we reckon it's a little sensitive for
damper UK days.

That's where the synthetic version comes in. It's slightly heavier
with a conventional zip and even a fleece-lined collar and less
sensitive to damp. Unfortunately it's not as warm as the down one.
There's notably less loft to the insulation and we reckon it's around
as warm as a 100-weight fleece, though it is windproof as well.
To be honest, we'd be more inclined to use a heavier synthetic
like the Generator with its greater insulation value unless it really
was quite mild.
One other thing to bear in mind is that the fit is quite small.
Even though Mont Bell go down a size from their Japanese fit for
Europe, we'd say that the men's medium is actually close to being a
small, so you may need to go up a size.
Interesting stuff that underlines why, for cold, dry
conditions, down is still king. The synthetic version of the UL
simply isn't warm enough in our opinion, we'd rather carry an extra
100 grammes and have a bit more warmth, though if you want the
lightest synthetic out there, this is probably it.
The down version makes much more sense from an insulation point of
view. It's insanely light and compact and still decently warm with it
and would be ideal for going as light as possible in a cold, dry,
environment.

In the UK you have to be careful to keep it dry, but it you're
prepared to do that and accept the limitations imposed by the quirky
press-stud design then you won't find lighter for the warmth. It's a
very specialist bit of kit, but does precisely what it's designed to
do.
The holy grail would be a synthetic with the same insulation value
and weight as the down jacket, but until synthetic insulation
develops further, that's not going to happen any time soon.

On this evidence, it's definitely worth keeping an eye on Mont
Bell, the company also has some great-looking sleeping bags using an
elasticated shell system similar to Mountain Equipment's. Oh, and its
catalogue is printed using soy ink :-)
Note: Available in the UK from OM shopping partner
Hike-Lite (see shopping section)
Know more or want to?
If you'd like to add your own experiences of this
product check out our user review system and post your opinions to
the world. If you have questions you can mail
us direct, ask
Richard Gear or try a posting to our
gear
forum.