This document specifies dimensions for metric ports for use with the adjustable and non-adjustable stud ends as described in ISO 6149-2 and ISO 6149-3.
Ports in accordance with this document can be used at working pressures up to 63 MPa [630 bar[1]] for non-adjustable stud ends and 40 MPa (400 bar) for adjustable stud ends. The permissible working pressure depends upon port size, materials, design, working conditions, application, etc. See ISO 6149-2 and ISO 6149-3 for pressure ratings.
NOTE The Introduction of this document gives recommendations for ports and stud ends to be used for new designs in hydraulic fluid power applications.

[1] 1 bar = 0,1 MPa = 105 Pa, 1 MPa = 1 N/mm2.