I had hoped these socks would be lightweight, yet thick enough to protect my feet over long distance walking, and they do!!  There are two layers of material, not bulky though.  Another thing I like about them is that they do not move or sink down at the heel as I walk.  So many other socks disappear into my shoes!  These stay put, which is a huge plus.
I am ordering more to get me through the spring and summer months ahead.  Love these socks!!!