These undies are unbelievable.  They deliver exactly what they promise.  My training partners and I sat on the sidewalk when were were done with a 5K.  When we all got up, there was all the proof the others needed to purchase these right away (I left no sweat print, but the others . .  . everyone knew exactly where they sat).  I loved them so much that I ended up buying 2 more pairs.  My only concern is that after wearing them 6 times, the elastic around the legs have started to shred.  The other 2 pairs are newer so I'm not sure if it was just a fluke or if they really don't hold up.  If you run in hot weather - these are a must have!!!