Now ND2 compatible! Notice - these are painfully sold in a single plug configuration! Order 4 as a set. 

These are recommended for turbocharged ND and ND2 vehicles. Direct HKS GT2 Supercharger replacement plugs. Reinforced by making the outer electrode bigger(see the pictures below). Also could have a steady ignition and ignition speed at a high load and high RPM by putting the center electrode in the middle of the spark plug. Ensured wide area of combustion by optimizing the position of the outer electrode and central electrode. It has a more efficient flame spread than the normal iridium spark plug.