evo.com | BlackStrap Long Underwear Bottoms > The BlackStrap Evolver Pant handles that tricky in-between stage where your kid's body's still figuring itself out. 4-way stretch and a slim fit move with them through growth spurts and activity changes, while flatlock seams sit smooth under layers with zero chafing drama. Slim Fit Flatlock Seams 4-Way Stretch Fabric (180gsm) 88% Polyester / 12% Spandex Odor-Resistant Machine Washable | Kid's BlackStrap Evolver Pants Unisex 2026 - Small Green | Spandex/Polyester