Kids’ Nike Junior Mercurial Vortex III (FG) Firm-Ground Football Boot Kids’ Nike Junior Mercurial Vortex III (FG) Firm-Ground Football Boot combines a synthetic leather upper with embossed ridges and an all TPU plate for the fit, touch and traction needed for today’s fast-paced game. Synthetic leather upper provides durability. Aggressive horizontal ridges embossed into the upper create friction to enhance ball manipulation. Full-length TPU plate provides durability and traction. Contoured, perforated sockliner provides low-profile cushioning that helps reduce stud pressure. Angular studs are designed for rapid penetration and release to facilitate bursts of speed.