Very comfortable, light but warm material but the reason I like a "mock" turtleneck is that it's not as high and full on the neck. This shirt's neck height is like a full turtleneck so I have to fold down the neck to make the height comfortable.
LL Bean's mock-turtlenecks are the perfect answer to keeping one's neck warm while avoiding the bulk of a full turtle neck. I just bought two more to add to my three that have been worn every winter for the past decade or so.
Love the tall selections. However I find that the sleeve length is barely long enough for a tall and the mock neck too large. With a 15-1/2 in neck i find it far to loose/large. I'm on the fence as far as the fabric feel. It's smooth like spandex!