What is the Proton LT?
If you're familiar with Arc'teryx's hugely popular Atom LT, you'll recognise where the Proton gets its good looks from. Don't get them confused though, these are two very different beasts! The Proton is designed with exceptional breathability in mind, whether that's as a midlayer in super cold conditions, or as an outer layer when moving quickly.
What is it made of?
Insulation: Providing the warmth inside the Proton is an air-permeable (wind passes through) Coreloft Compact 80 insulation. This synthetic insulation will still provide warmth when wet, will compress down to a fraction of its original size and is nice and easy to take care of. Coreloft Compact 60 is used in the hood to minimise weight and pack size where you require less warmth.
Outer fabric: The primary feature of the Proton is its Fortius outer fabric. Unlike the majority of insulated jackets which will feature a wind-resistant outer fabric, the Proton's is air-permeable, meaning air can pass through. This means that the insulation traps your warmth, but air can pass through to cool you down when you're working hard. Think of it like a tent; you open the vents to allow air to pass through to provide a comfortable micro-climate, much like the inside of your jacket. Despite its exceptional breathability, it will repel water and is tough enough to put up with the abuse that climbing and mountaineering have to offer.
What are the features?
Starting at the top, you get a helmet-compatible insulated hood, one chest pocket, two insulating hand pockets, a No Slip Zip (the zip won't slip down, if you hadn't already guessed) and dual hem adjustments to seal in warmth.
How does it fit?
Much like an Atom LT! If you haven't tried an Atom, the Proton fits into Arc'teryx's 'trim' fit block and is a regular/slightly short length, features plenty of room in the shoulders and feels brilliant when on. For reference, the centre back length is 66.5cm.
Where does it fit in the layering system?
The Proton, due to its fantastic breathability, can either be used as a warm midlayer with a shell over the top or an outer layer when moving quickly.
-
Exceptionally breathable
-
Water-resistant
-
Air-permeable
-
Two hand pockets
-
One chest pocket
-
Insulated hood
-
Dual hem adjustment
-
No Slip Zip