This is essentially the top half of the Sam Remo Speed Suit. I have lots of Castelli medium size clothing, so this a bit of an anomaly. I wouldn't have gone larger, but I could barely get the sleeves over my elbows. Size up if you have any doubts. Absolutely spray on. It necessarily has a strong zipper. I'd recommend the San Remo as an alternative as the overall aero effect is better. Good quality, but watch the sizing.