Reference Patagonia website for sizing info, worn maybe 3x. My son wore it from 2.5-4.5 years old when we had snow. Fit great even when big. He could probably still wear it but I bought the next size up already. one-piece for wet, cold conditions. Fully featured and seam sealed for snow sports, yet designed for comfort in any winter play. Fabrics, membrane and durable water repellent (DWR) finish are made without intentionally added PFAS. Made in a Fair Trade Certified™ factory. Waterproof Shell and Thermogreen® Insulation Fully seam-sealed shell is made of 100% recycled polyester that has waterproof/breathable H2No® Performance Standard protection and a durable water repellent (DWR) finish, with 150-g Thermogreen® 100% recycled polyester insulation to shield little ones from the cold; plus, the fabrics, membrane and DWR finish are made without intentionally added PFAS Built for Comfort Center-front waterproof zipper with an internal wind flap; soft tricot at the center back, inner neck and zipper garage provides warmth and extra coziness Grow-Fit Feature Intuitive Grow-Fit feature with elasticized cuffs at the sleeves and ankles folds up to shorten and folds down to extend, both by 1¼ inches, and helps keep the garment in play Pass pocket on the left sleeve has a hook-and-loop closure and a webbing tab to open and close with ease; one right-thigh pocket Built-in behind-the-knee articulation and a gusseted inseam Adjustable internal boot straps are easy to use and replace