 The boot is available in either Soft Ground (SG; now Soft Ground Pro/SG-Pro), Firm Ground (FG) or Artificial Ground (AG) versions.The SG version's sole plate is fitted with six NikeSnap removable studs, which can be purchased in different lengths, for the first and second models, and traditional screw-in aluminium studs for versions 3 to 8; the FG version has seven moulded blades.The origin of the Mercurial Vapors can be traced back to 1998, when Ronaldo debuted the original Nike Air Mercurial boots.