O-ring standards
AS568 vs ISO 3601 O-Ring Sizes
AS568 and ISO 3601-1 can appear similar in catalogs, but the designation, class and tolerance context matter. Use dimensions to compare; do not infer interchangeability from rounding alone.
AS568
US-origin dash-number sizing system used widely in aerospace and industrial sealing catalogs.
ISO 3601-1
International O-ring standard defining dimensions, tolerances and designation requirements. Class and application context matter.
Best practice
Compare the actual drawing/specification, nominal ID and CS, tolerance requirements and gland geometry before substituting one designation for another.