Swim cap
A swim cap is a form-fitting elastic covering worn on the head by swimmers during aquatic activities to reduce hydrodynamic drag, contain hair, and protect it from chlorine exposure.[1][2] Originally developed in the early 20th century from rubberized fabrics, swim caps evolved to latex models by the 1920s, which provided a tighter seal but were prone to tearing.[3][4] Modern variants primarily use silicone for durability and comfort or latex for minimal drag in competitive settings, with silicone caps being thicker and less likely to wrinkle while latex offers a thinner profile at lower cost.[2][5] Lycra or fabric caps serve more for hair protection in recreational use but provide less drag reduction.[2] In competitive swimming, swim caps are mandatory in many events to standardize conditions and minimize resistance, potentially shaving seconds off times through smoother water flow over the head.[1] A notable controversy arose in 2021 when FINA, the international swimming federation, initially prohibited oversized caps designed for voluminous hair textures in Olympic competitions, arguing they deviated from the standard head-conforming form essential for equitable hydrodynamics; the policy was reviewed and reversed for future elite events amid debate over equipment uniformity.[6][7]