00% Satin Inside Our Sizing Chart: NB: 0-3 Months > 13-16 inches XS: 3-6 Months >16-18 inches S: 6-12 Months >18-20 inches M: 1-4 Years >20-22 inches L: 5-10 Years >22-24 inches ADULT: 11+ Years > 24-26 inches