Marmot Bantomweight Jacket Review

Of course, products are getting lighter and lighter as technology allows new developments.  But, come on, 140 grams for a fully featured hardshell jacket – is that really possible?  Apparently so – the Marmot Bantamweight has landed and I was pleased to test one out in the recent UK autumn monsoon conditions.  Here is my review…..


The weight of any shell is predominantly made up from the fabric, and so the Marmot Bantamweight’s ridiculously light weight comes from the use of Pertex’s magical Shield fabric.  The Shield family is a selection of 2, 2.5 and 3 layer materials offering, as well as excellent wind resistance, high levels of waterproofness (20,000mm hydrostatic head) and high breathability (20.000 mm per m sqr/24hrs).  The material also features 2 way stretch for freedom of movement. The stats would match many other top end waterproof fabrics – except, that is, for the exceptionally low weight.

The Marmot Bantamweight uses the 2.5 layer version of this material and comes in several colours – I received a jacket in a lovely lemon yellow (called Citronelle), but Marmot also produce them in black, grey (Grey Storm), blue (Turkish Tile) and orange (Ember).  Understanding the way a 2.5 layer material is made is important to understanding how it will perform.  In a 2.5 layer material the waterproof technology is bonded to the exterior fabric and a coating or print is applied to the surface. This construction is lighter and more packable than 3-layer construction, but is inevitably less durable.

The Bantamweight uses C6 Durable Water Repellant (DWR) treatment which is a great choice. The DWR coating on a garment is what ensures water beads up on the garment surface rather soaking in and C6 is a more environmentally friendly choice rather than the more traditional C8 option that has been used by many manufacturers for years.  It is great to see manufacturers like Marmot leading the charge with the use of these newer treatment options.

Marmot were keen to strip the jacket to basic features and yet ensure that any essential features users would expect on a hardshell jacket were still there.  To this end, there is a full length water resistant front zip, 2 zippered side pockets, an interior mesh pocket that, as well as being big enough to store a phone, is also designed as a storage pocket for the jacket (a hook inside allows you to clip the jacket to a harness or rucksack).

Beyond that, there is a helmet compatible hood with stiffened visor and volume adjustment system, an elasticated hem adjuster and elasticated cuffs. All the seams are tape sealed and the front and rear logos are printed with reflective material.  There is everything needed and nothing you don’t. 

In Use

The first thing’s you’ll notice about the Bantamweight are the exceptionally light weight and the fabric’s soft drape.  At 140 grams for the man’s jacket, this certainly is very light and actually is the lightest hardshell jacket Marmot have ever produced.

This lightness obviously comes in significant part from the fact Pertex Shield is very thin.  This inevitably will affect durability and so will need users to think about what activities they choose to use the jacket for.  If you use it for biking and fly over the handlebars then the jacket surely won’t survive unscathed just as scratching it up a granite multi pitch route will leave its mark.  But, this is only the same as can be said for any light weight material and we can’t have it both ways – lightweight or durable is really the equation.  

The other thing you immediately notice about Shield is how soft the material is – forget your crisp packet type crinkly materials and be prepared for a quiet and silky fabric that sits beautifully and is very comfortable to wear.  I don’t know how Pertex achieve this, but it really is excellent.

The material is also, as mentioned earlier, a 2 way stretch fabric material allowing a complete range of motion.  This makes the jacket ideal for active pursuits and I have found it a great top for wet weather mountain biking just the same as using it for scrambling.  As long as you accept that durability compromise, then it is good to go for whatever you fancy.

Of course, that lightweight fabric also means that the Bantamweight folds up to next to nothing.  If you are looking for a jacket suited to fast and light adventures while still giving the weather protection needed for mountain adventures, then look no further.  It will fit in a biking pack, a waist pack, the pocket of your mountain trousers or clip on to your harness for multi pitch epics – the size and weight really allow the decision to take it along with you to be a no brainer.  

The fit of the bantamweight is, I would say, true to size.  I was sent a medium which fitted just right without being baggy on my 38” chest.  The stretch material also means that you can wear this a little tighter if needed.  The light weight fabric means the jacket sits neatly at the front with no bunching – you can see your feet when you climb!

There are no pit zips, but Marmot have considered underarm breathability by added some neat perforated holes in the armpit area.  This is a clever idea and, although I wondered if they would let water in, there has been absolutely no problem with that at all.  These vents, combined with the great breathability of the Shield fabric, give all the breathability needed.  The cuffs seal with a simple elastic system that works fine and the hem also does its job well.  

There are two zipped side pockets that are positioned high enough to not interfere with a harness or rucksack waist belt.  They work fine, but are actually one feature of the jacket I would happily live without.  I actually prefer to have just chest pockets in a jacket of this type, but appreciate that many users welcome side pockets.  They aren’t a problem for me, just not a feature I find too much use for. Marmot have also, I should say, added a small interior mesh pocket at chest height which, as well as being sized perfectly for a phone, also works as a storage pocket. 

The hood on the Bantamweight is excellent.  It is sized to fit over a helmet and it does that with no problem.  Of course, users aren’t always going to be wearing a helmet though and that is taken care of by a volume adjuster that pulls the hood snugly around the head.  It works really well.  

So,  all the features work as expected and the fit of the jacket is spot on – the final question is what of the fabric performance in wild weather?  Well, I have now used the Bantamweight in a variety of conditions from extremely windy to extremely wet.  I have also used it for a mix of activities from hillwalking to high output mountain biking.  It has been around the block.

My conclusion to the performance of Pertex Shield?  It is superb.  It keeps wind at bay and has fought off some very heavy and prolonged rain storms. I can’t deny that I was unsure a fabric this thin could fight off the worst of the recent UK deluge, but I really shouldn’t have worried.  It is completely up to the job.

Alongside keeping the weather out, what about letting the moisture that built up inside escape?  Perhaps the biggest test of its overall breathability came with a recent high output mountain bike ride in Snowdonia.  It rained most of the day and I was working hard on some steep climbs, but it kept me comfortable and mostly dry throughout the day.  I do say ‘mostly’ because the reality is that any breathable jacket, in very challenging weather, will trap some moisture in.  The Bantamweight certainly coped easily as well as other breathable jackets I have used over the years.


The Bantamweight is a truly great jacket made possible by the technical benefits of Pertex Shield.  To have a jacket this lightweight and yet this waterproof and breathable really opens up its use for many users and activities – as long as you accept that a material this light is prone to getting damaged in some circumstances.  Oh, and I really do applaud again the soft drape of the fabric. 

I also applaud Marmot for ensuring the jacket has the features needed to make its use efficient and comfortable.  It really means that there is no reason not to pack a waterproof jacket for every activity.  The Bantamweight costs £270. A women’s version is also available.

Posted by Paul