Originally Posted by pianomahnn

I too have some base layers from Under Armour. I don't know specifically which model of cold weather gear it is, but it's really thin, and has an almost unbelievable level of insulation. I have both upper and lower pieces, resulting in a full body cover; ultramegawarm.

In the weather the past few days (<0 degrees) it was no big deal. Pretty much the best piece of bike gear I've ever owned. Seriously.