"great warmth-to-thickness ratio; perfect body-hugging fit; great low-cut neckline"
My specific need was for a warm layer to wear undetectedly under professional clothing while working at a desk in my frigidly cold office. The Icebreaker Siren "sweetheart neckline" long-sleeve top fits that bill, and basically is a great-fitting, sweet-looking "f-u" to the meanies who keep my office building so darn cold all year round. I especially like the body-hugging fit of this top, and it warms my soul as much as my body when I think of how "green" the Icebreaker company is. Love it!