New THINX Period Proof Cotton Briefs Size L. NO tags. Use hip measurement to determine size. XS=2-4, S=6-8, M=10, L=12-14, XL=16. Holds up to two regular tampons' worth Outer shell and inner lining are 95% organic cotton, 5% elastane Middle layer is 100% polyurethane First, rinse; then machine wash, line dry