We stuff the PEARL iZUMi Pro Barrier Vest in our jersey pocket for a touch of protection against the gray clouds rolling in. When the wind picks up and the sky starts to spit we zip on this ultralight layer to mute icy gusts and shed moisture. The weather-resistant material still stretches and breathes to keep us comfortable on climbs while the close-to-body fit helps reduce drag. Plus once we've surpassed 10 miles we've already neutralized this vest's environmental impact.