Youth Sizing (fits 4-8) Quad-Ply Yarn™ Padding System below the transverse arch of the foot Strideline Heel Strap™ for fixed but flexible Achilles & ankle support Direct compression to help alleviate pain and soreness Zoned cushioning for cloud-like comfort in all the right places Contour fit thanks to stretchy shape-memory polymers Moisture wicking via mesh vents and hydrophilic fibers No stank = no worrying when taking your shoes off