The OMM Core Jacket is the first item of clothing we have used that features Primaloft’s NEXT insulating fabric, and by feature, we mean almost entirely made from this single fabric. Primaloft have a lengthy description about the finer details of the fabric with this particular section catching our attention. "Mimicking properties found in animal fur, constructed with fibers of differing lengths and deniers to create natural highs and lows in the material. This produces highly open structures that maximize airflow when on the move, and air entrapment when at rest, for optimal thermal performance."

When we first got our hands on the Core Jacket it appears that Primaloft’s NEXT is similar in style to that of Polartec Alpha although, on closer inspection, the weave looks more evenly distributed. It is clear to see why a brand with a high activity ethos such as OMM would opt to use a fabric such as NEXT and we were eager to see how it matched up against the similar products we have used in the past.

The Core Jacket packs small and weighs in at just 186 grams in a size medium. The fit is on the tight side which is great as this is a layer you want to have just above a thin base layer or directly next to skin. The NEXT fabric is soft and very flexible with full movement throughout and wears exceptionally comfortable. The stitching is in flat panels and seams are placed away from under the arms and on the shoulders to reduce any rubbing in these areas.

The instant the jacket is on you notice the insulation working impressively and for such a thin layer it really does pack in some warmth. As a stand alone jacket it performs at its best whilst on the move as the moment you stop a slight breeze will move straight through and remove any warmth built-up. Worn as part of a layering system is where it really worked best for us. The breathability is fantastic and placed underneath a waterproof or windproof outer layer it offers a great harmony of maintaining a comfortable body temperature and protection. Throughout the winter season we continued to reach for the Core Jacket as it was a perfect addition to our dry kit for comfort around camp and also to wear whilst sleeping.

For all the positives there are a few weaknesses which all come down to durability. The Primaloft Next insulation certainly doesn’t take much of a liking to any sort of abrasion or snagging. Flattening of the fabric is noticeable where the strapping of our pack or harness had been placed. Also, compared to one of the attributes of Polartec Alpha in that it seemed to improve in comfort when washed at home the opposite can be said of NEXT in that the fibres look to have clumped slightly. Although this hasn’t had a noticeable effect on the performance this isn’t a garment that looks to have a long lifespan without a good bit of care applied.

The two hand pockets for us can be regarded as almost unusable. We could neither easily fit our hands inside nor did we find them useful for placing items inside for fear they could damage the fabric. We would of much preferred if the pockets were removed completely with an extra saving on weight.

In regard to looks, there are a few colour options available with us receiving the Navy option. It’s a simple approach with sky blue on the stitching and zipper liner. We very much like this low-key approach and as far as colours go, these are in-offensive and stylish.

Our Verdict

The OMM Core Jacket works as either a stand-alone insulating jacket for the warmer seasons or as part of layering system through the rest of the year. The warmth to weight ratio is very impressive, so too is the ability to regulate temperature combined with additional layers due to the Core Jacket’s excellent breathability. There are questions over the durability but when it comes to comfort and functionality, we found we included the Core Jacket as part of kit for almost every expedition over the past 7 months.

Trek Scotland is a small family business based in the picturesque village of Tomintoul in the North East region of the Cairngorms National Park. They provide bespoke Mountain Guiding for Single Day Walks and Lightweight Multiday Trekking experiences, including wild camping, in the stunning Cairngorms wilderness and surrounding areas. Whether in the high mountains or lower valleys, their Multiday Treks are equipped with high quality, lightweight camping and trekking gear. They only work with small groups and, whatever your ability, pride themselves on designing your outdoor experience completely to your needs and with professional guidance and expertise. Adventure is waiting...