This is the lightest fleece in the test and yet warmer than many of the others. Berghaus has achieved this by combining a very simple design – just a zip-necked pullover – with a high loft grid pattern fleece – one of the many versions of Polartec Thermal Pro. The grid pattern, with its pillars of fluffy pile, is much lighter than a solid layer while being as warm. There’s a furry inner too, to maximise the warmth. The high collar is lined so it stands up.  The fabric is also very soft and feels very comfortable next to the skin. For warmth at minimum weight, this fleece is hard to beat. The packed bulk is quite low too. Combined with the weight this makes this an excellent fleece for backpacking. I missed handwarmer pockets but these would add weight.  The price seems quite high for a basic sweater but it’s due to the specialist fabric, which gives the garment its low weight and warmth.