This is pretty much the same Duofold as I bought 60 years ago.  It's still warm and comfortable.  I wouldn't call it "heavy", especially compared to some of the "expedition weight" fleece long underwear that's available, but it is perfect for wearing outside in cold weather when you're working or walking.  The fit is a little strange in that the waistband ends up a couple of inches above your navel, but that's nothing compared to some long underwear bottoms I bought from WallyWorld that had a waistband that almost reached my neck.  I much prefer these to underwear made of some synthetic material for normal active winter use.  They probably aren't heavy enough for just sitting around in zero degree weather or for riding a snowmobile in your blue jeans.

January 2016--Three years later, I'd have to change the star rating to two stars because the waistband totally gave out.  Only way I could wear these now would be if I gained around 80 pounds and it all went to my middle.  Too bad, because the fabric is still nice and soft.  I suppose I can cut them up and use the pieces to oil my gun or polish my car.