This standard presents information and calculation methods for the mass elastic properties and other characteristics of flexible couplings. This data is of importance to system designers for the selection of system components and natural frequency calculations. Calculation methods of the properties of the coupling flexible elements are not included in this standard. Due to the diversity of coupling types, this standard presents generally accepted practices rather than rigorous engineering analysis. Some characteristics are not covered in this standard, such as coupling balance which is covered in ANSI/AGMA 9000--C90, Flexible Couplings - Potential Unbalance Classification.