Lycra caps are fabric caps fashioned from the same material used in swimsuits. They fit smoothly over your hair. Unlike latex caps sometimes do, they do not snag or pull at your hair. Lycra caps do not keep water out, so you might feel some extra drag when you swim. The porosity of the material keeps you cool in hot weather, and they go on and come off easily. Lycra caps work well for younger swimmers who are sensitive to hair tugs and pulls.
Lycra caps cost more than latex caps, but they also tend to last longer. Rinse both types of caps with cool water in a sink or shower after you swim, and allow them to dry before tucking them away in your swim bag. Latex causes severe reactions in some people; symptoms include rashes and shortness of breath. You can opt for waterproof silicone caps if you have any concerns about the material.