Lots of thin layers keep you warmer than one or two thick ones, and Scott's Trail MTN 50’s lack of bulk makes it perfect for that. It’s definitely a mid-layer – it’s too thin for all but the mildest days – though with shoulders and sleeves of abrasion-resistant polyester, it can cope. The chest pocket is cut into a panel of the same tough material.
Despite the body being Polartec’s Power Dry, we found the Trail MTN 50 worked poorly as a base layer. The soft-backed material is comfy when dry, but despite enough gaps in that backing to make it see-through if held up to a light, it doesn’t deal with sweat well. Under other layers, it gets noticeably wet and stays that way.
Put it over a base and it’s a different story. It vents heat well, copes with moisture and stays warm without ever feeling restrictive. It’s very light, and scrunches small in a pack.
Sizing is good, and it’s close fitting without being tight – it slips between layers so well you hardly notice it’s there. A half-length zip adjusts heat loss easily, and a zip garage keeps the neck comfy even when it’s done right up.
The Trail MTN 50 could work well on its own on summer evenings, but for winter it’s best – in fact, very good – as a mid-layer. It’s well made, fits well and is an unobtrusive way of adding warmth without bulk.