The Castelli Men’s Tutto Nano Bibshort. Castelli’s Nano Flex 3G fabric is the result of a decade of development. It’s their best all-around fabric for winter tights warm stretchy luxuriously soft highly breathable and on top of that it features Castelli’s proprietary third generation of nanotechnology water-repellent finish. You stay drier and more comfortable. Even though this tight features Castelli’s latest water-repellency technology don’t think of it as just a niche rain bibshort. The fabric makes for a great dry-weather bibshort and the reduced-seam anatomical cut makes it extremely comfortable. Reduced seaming for improved comfort and fit. Mesh bib straps don’t hold moisture. KISS Air2 seat pad for long-distance comfort. Embossed logos for durability. 4deg-16degC 39deg-61degF.