A light material that's comfortable on sweaty skin and does not have irritating seams. Looks like it might snag if you get it caught on velcro so be careful with armbands and the like. I'll prob stock up on these for the gym and running. The short sleeved version is also comfortable and well cut.

Update: After putting these tops through some serious outdoor running and spin classes, I noticed that the fabric eventually gets drenched and sticks to your body (basically like cotton). Since this is supposed to be performance material, I had to knock off stars for that