TYR Ironman Multisport Women's Butterflyback Workout Bikini Butterfly back and thin straps are best suited for the A and B cup athlete.. Lycra shell is lined for comfort. Lycra functions as a preformance fabric which accommodates the majority of the body's vertical movements. This eliminates tension in stress areas such as the inseam, back rise and ensuring supreme comfort. Ironman logo on both top and bottom