This is a sport sock.  The bottom is thicker than a regular liner.  The top is thinner with a weave that would allow your foot to breathe without taking up more room.  It's easier to slip into a shoe without the wadding up that can happen sometimes.  Heel stays where it is supposed to--no slipping down in the shoe.  Where a toe seam would be, it's a little thicker but there isn't really a seam.  I appreciate that.  Good product and wearing is a breeze.