Will Renwick tries out Montane’s lightweight synthetic insulator

Montane and PrimaLoft have both joined forces to create this new reversible pull-on, a simple looking product that has a good deal of thought put into it.

The Fireball Verso uses PrimaLoft’s Silver Insulation Active: a mix of synthetic fibres that supposedly create an industry-leading warmth-to-weight ratio. It’s designed as an option for high-tempo activities like trail running and mountain marathons – a top you can keep in your pack without realising the weight, or even stuff into your pocket and then pull on for rests, on exposed summits or for evening camps.

I’ve found it absolutely ideal as an autumn day-hiking option – something I’ve been able to wear throughout a day without taking on and off. It’s kept me warm but hasn’t caused overheating on any hill climbs and it fits very easily under a coat, or even under another mid layer.

For overnights in autumn I’ve been relying on thicker insulated jackets instead, but I’ve still brought this along with me. When packed into its own stuff sac it’s only about the size of a pint glass and it weighs just 244.4g, so for quick trips I’ve had no problem with bringing it along as a luxury – a bit of added warmth.

Onto the reversibility. The Fireball I’ve been wearing is bright blue on one side and black on the other, and the reason for this goes far beyond aesthetics. The black side is lined with a Pertex shell which is windproof and retains body heat. The blue side, on the other hand, uses an air permeable quilted shell that means warmth isn’t retained quite so efficienty. Wearing it with the blue showing is therefore, quite literally, the cooler way to wear it.

Other features include an elasticated hem and cuffs (which also have thumb loops), a concealed chest pocket and reflective logos on both sides.

It comes in unisex sizes in either blue and black or in grey on both sides. Some might wish that there was also an option for a full-zip jacket version and/or a hooded version, but this would mean added weight and I think that would be going against the whole ‘fast and light’ ethos of the Fireball.


Reviewed in September 2015 issue