It could be argued that the most important aspect of a pair of tri shorts is the shorts' aero- and hydro-dynamic benefits. It all comes down to managing airflow, and coincidentally, the human body accounts for over 90% of aerodynamic drag on the bike and 100% of hydrodynamic drag during the swim. The good folks at Castelli are experts on aerodynamics, and the result of their expertise is the Women's Free Donna Tri Short. By combining a nearly seamless design with a low-profile, compacted thread Lycra, the Free Donna is nearly invisible to air and water, which, in turn, makes you faster.
The integrated leg grippers don't feel like they're binding your legs, as some grippers can. They hold your leg subtly, so you don't notice them as you ride, run, or swim. Castelli achieves this effect by knitting the grippers directly into the fabric at the hem, so everything lies flat and gently grips your leg without binding.
Rounding off the shorts is Castelli's triathlon-exclusive KISS Tri chamois. Castelli designed the KISS Tri to work most effectively while you're in the aero position on the bike. It trimmed away unnecessary foam to optimize comfort during the run and swim portions of your race. The removal of excess foam also allowed Castelli to make the pad wider, thus moving stitching away from the crotch to avoid irritation. A liner on the front of the short adds support to make you more comfortable during the run.
The Castelli Free Donna Tri Short is available in six sizes from Small to 3X-Large and in the color White/black/pink.