Recommended for high-pressure hydraulic oil line applications. Recommended Couplings: PCK Couplings (-4 to -16), Global Braid Couplings -GB (-4, -6 to -16), Field Attachable Type T Couplings (-4 through -24), GlobalSpiral™ Couplings, GlobalSpiral™ Plus Couplings, MegaCrimp® Couplings, Power Crimp® Couplings (-3 only), Stainless Steel B Couplings.