adidas F50 Sparkfusion League FG/AG JR3971 Football Boots. Part of the Coral Blaze Pack, these semi-professional adidas F50 football boots are designed for players who prefer to play on natural and artificial turf surfaces. The Fiberskin upper provides lockdown with an extended collar and features a Sprintgrid pattern on the forefoot. Lace closure. Textile lining. The Sprintplate Fusion outsole is designed to support biomechanics on a variety of surfaces.