Recommended for extremely high pressure and high impulse hydraulic applications. EFG4K exceeds requirements for ISO 18752 Grade D, SAE 100R12, EN 856 R12 and ISO 3862 Type R12. Recommended Couplings: GlobalSpiral Couplings (-6 through -20) Special One-Piece 20MGS Coupling (MC4-20 Crimper Only) (-20), Stainless Steel S Couplings.