Good materials, and I was excited to try this out -- I've had a few of the same model from a few years ago and they are the workhorses of my kit. I ordered a medium (5'11", 150lbs) and the fit was solid. But the new speed sleeves reminded me of a sphygmomanometer. I'm a cyclist, nobody has ever accused me of having "guns", or for that matter ever even commented on my biceps. However, the cuffs on the speed sleeves were tight enough around the brachial artery that I was worried I'd lose circulation to my fingers after a minute or two. While this might stretch out after a while, it's just not something I feel like dealing with. Other brands have form-fitting sleeves that fit just fine, I think PI just got a little too aggressive on this go around.