Engineered to Provide the Ultimate in Long-Distance Comfort Castelli have engineered a new fabric that changes depending on the needs over various parts of the body. The lower leg has a raw-cut leg ending and rubberized yarns to guarantee a flat grip to keep the leg in place. The fabric becomes lighter in the thigh, while the four-way stretch provides just the right amount of muscle support. In the pelvis area, the compression and support increase to keep the seat pad and everything else in place, and the fabric gets thicker to avoid any embarrassing transparency issues. Progetto X2 Air Seamless Pad The seat pad is Castelli’s top-of-the-line Progetto X2 Air Seamless pad. It's actually two separate components: a soft, stretchy Skin Care Layer next to your skin, which has the sole purpose of preventing any rubbing on your skin, and, under that, the Cushioning Layer, which features two separate densities of foam along with breathable perforated gel inserts under the ischia bones and perineum.