Perfetto by Name, Perfetto by Nature It was the Castelli Pro riders who first asked for a Gabba that’s not as hot as the original but warmer than the Perfetto Undershirt. So with the Gabba as a starting point Castelli have made the back in Nano Light fabric - the same fabric as their Nano Flex pantyhose but without the brushed fleece inside. This gives the piece a lot of breathability and keeps you from overheating inside. By using a lighter weight of Windstopper (a full 25% lighter than the one used on the Gabba) on the front the overall weight was further minimized. You may think that this is filling a very small niche. But just try it. It can cover most of the conditions of the Gabba (except wet racing and very cold), yet it handles warmer temperatures better. And the fit is exceptional, which is one more reason you’ll keep reaching for it. The consensus of the Castelli test crew is that this piece doesn't fully replace the Gabba or a Perfetto undershirt but it’s another arrow in your quiver that is ideally suited to cool temperatures, especially when it’s dry or there’s a risk of light rain. Windstopper 150 Fabric Light elastic protection from Castelli’s lightest Windstopper three-layer knit fabric. Total windproofness, excellent breathability, functional stretch and DWR coating for water repellency, this fabric has opened up new possibilities in constructing layered garments for enhanced fit, temperature and moisture management.