Terramar Polypropylene 2-Piece Long Underwear Set - Kid39;s Mesh Constructed of moisture-wicking, cottony soft 100% polypropylene. Fabric has EC2 Qwik-Dri Thermoregulation Comfort Technology. Flat-seam construction for added comfort and durability. Provides UPF 50+ sun protection. Anti-microbial treatment for odor prevention.