The Syncrino Base layer LS Tee is made from 53% polyester and 47% merino 125 wool. It doesn’t feel quite so warm as the tops I tested that were composed of a higher proportion of merino, but I feel this is probably due to the fit rather than the material. Although it is described as having a ‘slim’ fit, this top is noticeably looser around the middle and just above the waist. Whilst this might feel welcome in warm conditions, the lack of skin contact with the fabric here will be missed when it is colder. Of course, this may just be due to my own shape, and the top will fit differently with different body shapes.

This is the stretchiest Men’s base layer in this round-up. Both the fabric and the seams allow a good amount of stretch, and this is a real positive if you are using this base layer for technical activities such as climbing or scrambling. The fabric is soft to the touch and extremely comfortable, and yet is clearly hard-wearing and durable. The seams are densely stitched and cause absolutely no chaffing or itching. However, there is a small, clear plastic tab on the neckline which I found a little irritating at times. The sleeves are on the long side, and I felt they could have benefited from some thumb loops.

Price: £65 | Weight: (Size medium) 160g|  Materials: 53% Polyester (32% recycled), 47% Merino 125 wool | Features: Slim fit, single jersey fabric construction, stretchy seams. | Sizes: S-XXL | Women version: Yes | rab.equipment/uk

Breathability was extremely good, as was odour control. Overall, the top was quick drying. However, I did find that it retained some patches of moisture that took quite a lot longer to dry than the rest of the garment. The end result was that this was the slowest Men’s base layer to dry in the round-up by a small margin.

I really liked that the Syncrino Base LS Tee comes in minimal packaging. It is sold in a small, fully recyclable brown paper envelope, as opposed to a two-piece box as was the case with some of the other garments. I also noted that 32% of the polyester component of the fabric is recycled. This is a durable and highly comfortable base layer, particularly well-suited to technical activities in the mountains that benefit from wearing a stretchy top such as this.