These are very warm, very snug and highly-wicking baselayer tops. They perform well, are hard-wearing, don't shrink when machine washed (40deg), last for years and there is no 'itch' from the merino wool. Thanks to the Lifa lining they wick much more effectively than merino alone but benefit from the merino outer - ie they combine the best of both materials.
The only issue I had is related to the sizing. Normally I wear a small in the Helly Hansen range but the exception is in this specific design with the 1/2 zip where even the medium is a tight fit. The usual small size was not only skin-tight but also most uncomfortably constrictive and I felt the fabric stretch even in order to breath! The medium is a close fit but comfortable. For anyone ordering this style, I recommend ordering one size larger than normal for a close, skin-touching fit or two sizes larger for a looser fit.
See my uploaded photos illustrating the size difference between three different designs, ie 'Dry', 'Warm' and 'Warm 1/2 zip'.