... Popular in USA,EU,Indonesia,Brazil,Austrilia. 3.Excellent quality. spark plug c7hsa1. Multi-ribs of insulator eliminate flashover. ... shock, great mechanic and electric features, super insulation.3. Nickel plated housing prevents oxidation and corrosion, heat ... corrosion, good electric and heat conductivity, prolongs spark plug service lifespark plugs Low QualityHigh QualityInsulatorAlumina Content 87%- ...