"Great breathability and moisture control, wind will cut right through"
This is a great beanie if you understand what it is and use it as intended. If you are expecting this beanie to protect you from wind you will be sorely disappointed. The phase AR material does a good job at trapping your body heat and handling moisture. I have recently taken this beanie on a couple of runs where it has been 35 F, drizzling/flurries with a bit of wind and it performed great. It should be noted I was wearing my incendo windbreaker so when I noticed the wind was cutting right through it I just put on the hood to cut the wind and went on about my business. At no point during my run did I feel the need to put on my heavier toque because my own trapped heat was enough. It wasn't until I got back home that I noticed that I had sweated a little and the perspiration was spread out across the front part of the beanie. During my run the sweat did not run down nor did I feel my head getting damp, the beanie worked as intended.
"Finally a thin poly beanie in more than 'one size fits all'!"
In search for a thin, breathable poly/fleece beanie, a common theme is 'one size fits all'. My noggin is on the larger size and found most decent options from Outdoor Research, Rab, Patagonia, etc. only came in a single size that was always too tight (even with some stretch). I have been a long time user of Capilene so was a bit unfamiliar with Arc'teryx Phase fabrics.The fabric has a dual weave similar to that of a Cap 2. The inner is more open knit while the outer has a much smoother close knit texture. Each layer is a bit tighter weave than the corresponding layer on Cap 2 but is essentially the same thickness. Very thin overall. Great breathability and moisture control.Will be curious to see how the Phasic fabric holds up long term but no concerns thus far.Did I mention you actually have a choice of sizes?