Active muscles require extra cooling in order to provide sustainable power, especially during hot conditions—Castelli knows this. Incorporating seven different varying-thickness fabrics, Castelli's Inferno Bibshorts maximize cooling and provide lasting durability. Their comfortable Progetto X2 Air chamois allows ease of motion and extra airflow, while their Free Bib design minimizes the bib uppers, allowing for an open chest. Titanium dioxide, the active ingredient in many sunscreens, is infused into the thin fabric to help deflect sunrays and protect you, though it's still recommended that you apply sunscreen underneath—because the fabric is that thin and cool. These airy bibs also sport Castelli's GIRO3 elastic leg grippers for a comfy, secure fit.