The A3 Performance Flashback and Xback is great for competition, training and lap swimming. See photos for the backs. Flashback has less coverage with thin straps at shoulders and across the back. Xback has thin straps but a thicker band across the back. Flashback tends to be more popular with older girls. Made of the ideal blend of chlorine-resistant polyester fabric and made with four-way stretch that provides great color fastness and excellent fit. Comfortable, lightweight and durable...the Xback will go the distance! 52% Polyester / 48% PBT, front lined.