If you're a triathlete, you take on the challenge of being good in three sports: swimming, cycling and running. In order to do this, you have to spend time perfecting the skills of a swimming stroke to propel you through the water, pedal stroke to glide through the wind on a bike and finding the most efficient stride to get you to the end of the race ahead of others. These skills must be accommodated with the right type of clothing. Castelli designs triathlon clothing that can move with your body in all three legs of a triathlon. This clothing keeps you comfortable whether you are swimming through water, time trialing on a bike or kicking it on the run. Castelli offers clothing specific to each leg of the race or a one-piece suit you can wear throughout the entire triathlon. Triathletes who do Ironmen usually switch clothing since the few seconds lost in the transitions don't make as much a difference. The sprint and middle distances can be most efficiently tackled with a one-piece that stays on and keeps you comfortable in the swim, on bike and run. One popular change is slipping on bike shorts after coming out of water. The Castelli Free Tri-Short is designed to handle the water because the shorts don't absorb water and they dry almost immediately in the transition. If you prefer to swim without the shorts, the Free Tri-Short is easy to slip on and it has just the right amount of padding when in the aero position. In the run, this padding nearly disappears so there is no interference on the run. The men's and women's Tri Shorts have gender specific designs for maximal comfort and protection. The Castelli Free Tri Top for men is a sleeveless full-length top made with quick-drying fabric that fits like a second skin so there is no interruption in the water or wind. The Free Tri Top for women is a half top that allows maximum air to keep the woman triathlete's body cool and dry. This top feels like a second skin and dries immediately. The Castelli Free Tri Singlet for women is a sleeveless top with back jersey pockets. The Castelli Alii Run Top for men and women has no pockets and is exceptionally lightweight. The Castelli Free Sanremo Short-Sleeve Suit provides a full-piece suit that minimally absorbs water in the swim and has the right padding for the time-trial position and has fabric that allows air flow to keep you cool on the run. In the case of a non-wetsuit suit, short sleeves are not allowed in the swim. Yet, this can be fixed with the Sanremo Suit that is designed so you can easily unzip the top and roll it down to the waist. The advantages of the sleeves comes on the bike where the triathlete is more aerodynamic with the sleeves creating a smooth surface for airflow. The Castelli Free Sanremo Sleeveless Suit has all the same features, minus the sleeves which make it acceptable in the swim and cooler on hot days. Both Suits have plenty of storage space for food. The Castelli Free Tri ITU Suit is probably Castelli's fastest speed suit. Frederik Van Lierde won the 2013 Ironman World championship in the Free Tri ITU Suit that is made with fast, breathable fabric and a zipper on the back which doesn't interfere with any movement.