TYR Baja Thin-X Back (24-28 Only) TYR Baja Thin-X Back (24-28 Only) TYR Baja Thin-X Back The Baja Thin-X Back Swimsuit utilizes a thin strap design, for reduced drag and maximized support. Engineered for training and fitness routines, the TBAB7 women's swimsuit lasts 20 times longer than traditional swimwear and is 100% chlorine proof for 72 hours of exposure.