Weight: 115g (m)

Best for: Fast and light pursuits and as an ultralight spare layer.

Overview 

The ultralight Core is constructed from Primaloft Active 75gsm, one of the latest generation of highly insulating, ultra-compressible fleeces. Using a polyester plume woven through a knitted mesh, this innovative fabric mimics animal fur and reduces the need for clothing changes. This minimalist technical garment has a body-hugging fit and a cosy hood but no pockets or extraneous weight-adding details.

Performance 

Primaloft Active is similar to Polartec Alpha, which was developed for the rapid stop-start activity of special forces soldiers. The Core is so light and unrestrictive you hardly notice you’re wearing it. When you’re stationary the loosely woven lofty fibres provide remarkable insulation, and during movement the open weave allows generous airflow, which delays overheating. At walking pace you can feel air passing through it, but when paired with a windproof layer its insulation value for weight is obvious. It’s ideal as a high-performance midlayer on bikepacking and tramping trips, and I’ve found it also works well as a baselayer directly under a shell on wet days, when its rapid venting helps with temperature regulation. 

What we liked: Super warm for its weight, highly compressible, very breathable, fast drying.

Limitations: Expensive, fabric prone to snagging on rock and scrub, no wind resistance.

Why buy the Core? 

This fleece is exceptionally warm for its weight and size, making it a go-to when saving grams is a priority. Trampers and cyclists will also find it useful as a light but cosy spare base- or midlayer.   

Overall Score: 80%