The Montane Prism Jacket is the lightest hooded synthetic fill jacket on the market – just 12.9 ounces in a size large. If you are looking for lightweight synthetic insulation that you can wear while hiking, keep reading. There are few jackets targeted so nicely to that function. But if you are looking for a puffy insulation piece that will keep you toasty in the coldest of temperatures, look elsewhere. The key feature of the Prism is its very light, low loft, synthetic fill insulation – much lighter than insulation used in any of its major competing jackets. Montane has combined this insulation with a Pertex Microlight shell, a full zipper and enhanced breathability panels; all features designed to make this a jacket you can wear (in the right conditions) while hiking or climbing – without getting overheated. The Prism also includes an insulated hood, an unusual combination with a jacket focused on lightweight insulation – but a feature that adds significantly to the jacket’s versatility. Of course, the light insulation means the Prism has less loft and a lower loft to weight ratio than many other synthetic fill jackets. I took the Prism out on a series of cold weather trips to find out how it performed under diverse cool weather conditions. I wore it while hiking, sleeping and just hanging around camp; on some trips I rarely took it off. The photo at right was taken on a New Year’s Eve trip in the Santa Catalina Mountains of southern Arizona.
- The lightest hooded, synthetic fill jacket on the market
- Hand warmer pockets are placed high enough to use with a waist belt
- Insulated hood is comfortable and adds to overall warmth and versatility
- Breathability panels, light insulation, full zipper and Pertex Microlight shell make this a breathable insulation piece that can be worn during aerobic activity
What’s Not So Good
- Light weight comes at a price – low loft to weight ratio
- Some stitching flaws in our sample
|2006 Montane Prism Jacket|
|Hooded synthetic fill jacket (with full length zipper)|
|0.78 oz/yd2 (25 g/m2) Prism insulation|
|0.25 in (0.64 cm) single layer loft|
|12.9 oz (366 g) as measured, size large, manufacturer’s specification 12 oz (340 g), size medium|
|Pertex Microlight outer shell (1.4 oz/yd2, 45 g/m2), PEAQ Air breathability panels and inner shell|
|Insulated hood with drawstring closure, beard guard, full length zipper, two zippered handwarmer pockets, hem draw cord, drop tail, breathability panels under armpits, reflective panels on shoulders|
|$145 US (approximately), 75 Pounds, € 110|
I spent a lot of time testing the Prism under stressful aerobic conditions. While it is easy to get overheated in any jacket if temperatures are too warm, the Prism is a good choice when hiking with temperatures up to about 50 degrees. Even when I am really pushing hard up a hill, I can stay cool and comfortable – although depending on conditions I may have to open the front zipper. On a windy and wet day, with 40 to 50 degree temperatures, I wore this jacket with just a silkweight Capilene t-shirt as a base layer, and was warm all day. During an aggressive 700 foot climb I opened up the jacket, but did not get overheated. When the wind really picked up, I pulled up the hood. The Prism really shines under these conditions – a single layer, less than 13 ounces, filled my insulation needs for the day. The Prism overlaps the functionality and performance of a softshell, at a similar overall weight, with less bulk in your pack, and includes the hood which is lacking in most softshells. I also used the Prism in colder conditions – slushy snow and rain just above freezing. The Prism does well in these conditions; I was warm, dry and comfortable all day – but I carried a waterproof shell and donned a vest when I rested. I also used the Prism as part of my sleep system on a couple of trips. The hood is very comfortable while sleeping and significantly adds to the overall versatility of this jacket. I had initially questioned the need for a hood on this jacket – why not eliminate it and knock off another ounce or two? But without the hood, the Prism would not be nearly so warm as part of your sleep system. The Prism jacket also serves well as emergency insulation for day trips or alpine climbs. Here the low bulk, light weight and hood make it an attractive choice.
The Montane Prism has two zippered handwarmer pockets that are placed high enough for use while wearing a waist belt. The Enhanced Breathability Panels can be seen under the armpits.
The Prism insulation was designed by Montane to be light and indeed it is very light when compared with other leading lightweight synthetic fill jackets. At 0.78 oz/yd2 (25 g/m2) the Prism insulation is half the weight of the insulation used in the very light MontBell Thermawrap series. Prism insulation fibers are treated to improve stability so that the insulation does not need to be quilted to a carrier fabric – saving weight and helping to maintain loft. The insulation is sewn to the garment lining to keep it near the body where it is most effective. Both the inside and outside of the hand warmer pockets are insulated. This reduces heat loss when the pockets are open, and adds very little weight or volume.
The Prism has a complete list of features, starting with its hood and drawcord. The hood can be cinched down easily, with pull cords on either side. The hood can be rolled up and secured with a Velcro tab when not in use, keeping it out of your way. Below the chin there is a comfortable beard guard. The Pertex Microlight shell is soft and nice to the touch – and also surprisingly durable. On one recent trip I spent a lot of time hiking in long grass and thorns. At first I was very careful with the shell material, holding each branch carefully so it didn’t drag across the shell fabric. But later I gave that up and plowed through bushes with little regard for the shell material. The shell showed not a single run, snag or cut. I was surprised and impressed. The shell is DWR treated and felt completely windproof on several windy days. Under the armpits are two panels, which Montane refers to as enhanced breathability panels. These panels use PEAQ Air as the outer shell, a lightweight nylon rip-stop that is more breathable than Pertex Microlight. At the rear shoulder of these panels is a small Scotchlite reflective panel. The interior lining is also PEAQ Air. The hand warmer pockets are placed high to make them usable while wearing a waist belt, and each has a full zipper. I could easily use the pockets for storage or to warm my hands while wearing a waist belt. I thought the relatively high pockets might be uncomfortable, but I find them comfortable even when I am not wearing a pack. Like most Montane garments the Prism has a significant drop tail; a nice feature if you are resting in bad weather. I find the Prism to be a little shorter in the torso than many other garments. If I ordered one again, I’d get an extra large for my 6’4” frame. The Prism stuffs easily into the right zipper pocket (only the right pocket has a double sided zipper pull). The cuffs have a simple elastic closure – but I would prefer a lighter and smaller elastic. There is a drawcord at the hem with a pull closure on either side. The drawcords operate easily, but I found little use for them in the conditions I encountered. The overall construction quality is good, but my sample has a couple of stitching flaws around one wrist causing some fabric to bunch up on the cuff.
The Prism has an aggressive drop tail that helps to cover the rear. Note that this garment was slightly undersized for the author and a proper fit will provide better coverage than shown here.
As you would expect, the Prism suffers when used as a pure insulation piece. It is not the best choice for efficient insulation while resting with temperatures below freezing. And with its full set of features and light insulation it is clearly not designed for that role. But for cold weather activity, it fits nicely into a niche not occupied by many (if any) synthetic fill garments; the MontBell Thermawrap Action jacket is perhaps closest to the Montane Prism in overall design and target use. The Thermawrap Action jacket is about an ounce lighter, but does not have a hood.
The Prism is not currently available in the US – but with a little searching on the internet you should be able to find a European retailer who will ship one your way.
The Prism stuffs nicely into the right pocket. The stuffed pocket can be zipped shut for convenient storage. The small volume of the stored jacket is attractive when considering this jacket as emergency insulation to be stored at the bottom of you pack.
Very light insulation and breathability features such as the PEAQ panels make this jacket appropriate for high exertion levels – a function not supported as well in other synthetic fill jackets. At just under 13 ounces, this is the lightest synthetic fill jacket that includes an insulated hood.
Recommendations for Improvement
Without negatively impacting its performance, the Prism could be made lighter. The drawcords, zippers, zipper pulls and cuffs could all be simplified to make this jacket lighter, albeit somewhat less durable.