Our Kids&'; Classic Thermal Merino Base Layer Bottom uses our super soft Mid 250 interlock knit-perfect for layering in cool conditions and great for wearing alone on a mild day. Now your kids can be as warm, dry and comfortable as you are. In your SmartwoolA(R) base layers. Features Slim Fit 100% Merino wool fabric made with an interlock knit for enhanced comfort, breathability, thermoregulation, and odor resistance Merino-covered elastic waistband adds comfort Flatlock seam construction designed to minimize chafing Size M - Inseam: 20" (51 cm) Knit in Vietnam: 100% Merino Wool Style: SW0SN112