You've almost certainly heard the term, free speed bandied about in regard to aerodynamically designed products. We're not experts, but something you have to buy certainly doesn't equate to free in our book. Semantics aside, the concept of a component providing a speed advantage via design isn't new, but its application to clothing is somewhat new, and the Castelli Free Aero Women's Shorts are a perfect example. At their core, they're as good as every pair of Castelli shorts we've tried, which is to say durable, flattering, supportive, and comfortable in equal measure. But, beyond that, the contoured cut and some fabric magic team up to deliver a savings of 10 watts at 50kph, which means that if you're in the breakaway, you're spending less energy to go the same speed as the other riders with you. It doesn't sound like much, but compounded over even an hour long crit race, you'll be just a bit fresher when it comes time to sprint.