Castelli have re engineered every aspect of the free aero race bib shorts now more comfortable and aerodynamic than ever before the shorts are incredibly comfortable and improve muscle support without constriction the giro air leg bands provide increased stretch and distribute stretch and compression over a wide area vortex dimpled fabric on the legs improves aerodynamics while the 30 lycra body construction offers excellent stretch the progetto x2 chamois features an all new soft surfa