I have several Defeet WoolEater bike socks and absolutely love them as the best socks I own. I wear them daily, even when I am not cycling. So out of curiosity I thought I would try their arm skins. I am slim and the XS fit great and didn't droop or itch during the ride, even though I worked up quite a sweat! They kept my arms toasty warm and never felt clammy or too roasting, even when the temperature rose. I like the unfinished seem at the top because it doesn't bind like a seemed edge might. I was a little careless and frayed the material when I pulled them off, unfortunately. I got mine on sale, even less than other synthetic arm skins, but wool is ooohhh soo much better. I wish they made leg warmers, my current wool leggings are too droopy. These have just the right amount of Lycra to make a nice fit.