Castelli's Nanoflex water-repellent fabric is one of those fabrics that seems miraculous. On a dry day it's as warm and breathable as their normal Thermoflex fabric, but when it rains the water just runs off, thanks to the five-phase nanotechnology treatment. They've used an innovative construction for the Castelli Nanoflex Bib Knicker that minimizes seams to keep you as dry as possible. While it's not 100% waterproof, it's the best solution Castelli have ever tried for staying comfortable in any condition. The KISS3 seat pad features an anatomic shape to conform to your body and ultimately increase your comfort. A continuously variable thickness eliminates the odd sensation of ''thick here, thin there'' that you may have seen before with a dual-density pad. The brushed microfiber cover cuts down on chafing and features a bacteriostatic treatment to reduce the likelihood of saddle sores. Bibtight and knicker: GIRO3 grippers position the tight and seal around the shoecover, while on the knicker the grippers help the fabric stay put without binding. The mesh bib straps help transport moisture to the jersey and make sure the waist stays where it's meant to be. Reflective Castelli print and reflective tape zippers make you more visible in low-light conditions.