So most of us like to have a couple of cool football shirts around. I've got Adidas Techfit, Climacool and Nike Dri-Fit shirts. After playing for about a year and circling through them, I've found them to be very different in terms of warmth and moisture regulation, as well as lightness. Some technicalities, as to make sense of my comment about the shirts fitting: I'm 180 cm's (5'11"), weigh somewhere between 70-72 kg's (no idea how many pounds). I'm not overly muscled, but well formed. My fat percentage, though I haven't measured it for a while, is around 17%. All the shirts mentioned here are sized M. Adidas Techfit (without PowerWeb): I've the Chelsea Home and Away from the 10/11 season. I love this fabric, it fits like a glove and it looks insanely cool (if you're skinny enough, hehe). The tight effect makes me feel like the hulk, which (I'll just admit it) gives me a mental boost. Downsides? The shirts have a tendency to crawl upwards during play. Adidas Techfit (with PowerWeb): France Away 2010 jersey. The PowerWeb is an interesting feature, which is supposed to support you. I suppose I don't play on the level where this will really make a difference, but the support is definitely there. Does it make me play better football? Nope, haha. Does it feel good? Definitely. Adidas ClimaCool: AC Milan Home 11/12. Dang this shirt looks ace and fits perfectly. Good length, but not too long. Loose, but not too loose. Nike Dri-Fit: Netherlands Home 2010. OK, so the Techfits fit better (duh). Adidas generally looks cooler. But this shirt blows the others out of the water when it comes to moisture regulation, lightness and temperature control. I play mostly indoor, 90 minutes with some breaks. Sure I sweat plenty, but it's mostly gone at the end of the evening. I forget I wear this shirt. With the Techfits, you're constantly aware you're wearing them (which is part of the idea, especially with PowerWeb). However, even in ClimaCool I still get rather hot. Not so with this Nike shirt: it's coolness all evening. Those are my experiences. What have you guys got? Anyone have experience with undershirts, as well? P.S.: I got my hands on a Inter Away 2010 jersey, sized M. Surprisingly it was HUGE compared to my Netherlands shirt, which is also in M. How can there be such a difference in sizing? Anyone have a clue?