The castelli nano light bib short was made for spring conditions when your riding goes from long winter rides in tights to higher intensity and youre riding no matter the weather this short is made with castellis nano light pro fabric and unbrushed version of their nano flex fabric this fabric has a tighter weave so it keeps out more water and the 270g weight makes this good for cool weather as well as providing great muscle support theyve minimized the seams to help keep the water out