I have been using it for running for more then a year in 2-8 degree and found it extremely comfortable and warm with one top layer.
very good material breathable
This is a brilliant base layer that fits true to size. I am 6' 2" and 14 stone and the XL is a perfect compression fit. I bought a short sleeve version a couple of years ago, which, has proved to be the best base layer I've ever bought.I use this top as a base layer when cycling and I sweat, A LOT, (not pleasant!), but these tops dry so quickly that when combined with a good cycling jersey I don't get cold. They wash well and retain there shape even after three years! I've just bought two short and one long sleeve for the coming cold weather, not that we've had much warm weather! At the sale price just buy one, even at the normal price you will not be disappointed, these are as good, if not better than more expensive brands I've used.
Good fit, comfortable material, does the job!