I bought these to wear under my kevlar motorcycle pants that are pretty rough around the knees, and they are absolutely perfect.  Soft to the touch and thick enough to soften the knee armor, but light enough that you don't sweat in them until it gets to 75 degrees or so.  Perfect for late spring/ early summer rides here in the Seattle area.  I also wear them when I umpire Little League baseball and softball, under the shin guards, and they are perfect for that as well (I had been having to put large Bandaids on my knees to keep the shin guards from chafing).  Just a great all-around under layer in all but the warmest weather.