Craft Size Chart The Breakaway Singlet is a highly functional running singlet crafted for dedicated athletes who run with a purpose. The singlet is made of soft, functional polyester and a has an opening at back for enhanced ventilation. In addition, it features a flattering rounded hem as well as elastic edging at the collar and arm openings. Features: - Soft and functional polyester - Efficient moisture transport - Opening at back - Elastic edging - Fabric 1: 91% Polyester 9% Elastane Fabric 2: 100% Polyester