SR4U Color Changing Laces start out as white until you go outside. When the laces are exposed to the sunlight they will transform into another color right before your eyes. When going indoors or into the shade they will transform back to white. They are a direct replacement lace for all soccer/football boots including Magista Obra, Mercurial Superfly, Hypervenom Phantom, Tiempo Legend and all other soccer/football boots. The laces are 100% Polyester and are 47 inches or 119 cm in length.