AS 568 is an Aerospace Standard used in the United States that specifies the inside diameters, cross-sections, tolerances, and size identification codes for O-rings used in sealing applications and for straight thread tube fitting boss gaskets.
ISO 3601 is a standard issued by the International Organization of Standardization that specifies O-ring dimensions in metric sizes.
PTFE Back-Up rings come in single turn, multi-turn, and solid configurations. Back-Up rings follow the AN6224, AN6246, MS28774, MS28782, and MS28783 specifications
X-rings (Quad TM-rings) use the AS 568 and METRIC standards for dimensions. The groove dimensions are slightly different, and can be enlarged up to 15%.
JIS B 2401 is a standard issued by the Japanese Standards Association that specifies O-ring dimensions and standard materials.
GB/T 3452.1 is a standard issued by the Chinese Authority that specifies the inside diameters, cross-sections, tolerances, and size identification code for O-rings used in fluid power systems.
BS4518 is a metric standard issued by the British Standards Institution that defines dimensions for O-rings and their housings for rod, piston, face, and trapped grooves.
SMS 1586 is a Swedish Mechanical Standard that specifies O-ring dimensions. The O-rings are identified by ID and C/S, and are classified for type D or S applications.