Back for its second generation, the Castelli Men's Idro 2 Jacket retains the legendary waterproof protection and outstanding breathability of Gore-Tex's Shakedry membrane, but it's lighter than ever and features a subtle redesign in graphics along the backside. The Idro 2 Jacket builds on the successor's ultra-lightweight, highly compact shell by shaving approximately 16 grams from its design and taking up only half the space of a rear jersey pocket when it's folded inside. Besides being lighter than an afternoon snack at a mere 107 grams, the Idro 2 Jacket retains the Gore-Tex Shakedry membrane, which places the waterproof, breathable membrane on the outside of the jacket, thereby preventing the chance of it wetting out when it's subjected to hours of heavy rain. And because Shakedry is one of the most breathable constructions in Gore-Tex's line, you'll enjoy won't feel like you're wearing a sweaty garbage bag, especially on long climbs where overheating is commonplace. It's rounded out with a waterproof YKK Vislon zipper, plus reflective highlights that pop on those dreary days with rain and ominous clouds.