- Keen Kids Size Guide - Let little feet sense their world with versatile style in the Keen® Kids KNX Middie Easy On Strap Comfortable Barefoot Feel Sneakers. The minimal, flexible KNX feeling can improve balance through increased ground contact, now in a new, elevated look. Featuring a mid-top design, an adjustable hook-and-loop strap, and a lightweight "barefoot" feel, the KNX Middie kid's sneakers are built off KEEN's traditional wider footwear form. - Leather upper. - Polyester lining and insole. - Leather Working Group certified. - Heel pull tab for easy wear. - Rounded toe design. - Rubber outsole. - Imported. Measurements: - Heel Height: 3⁄5 in - Weight: 7 oz - Product measurements were taken using size 4 Toddler, width M. Please note that measurements may vary by size.