"Underbust Width" is measured horizontally across one side of the garment when laid flat, below the bust support area, and does not include the bulging part of the cups; the values in the table represent the range from laid flat to lightly stretched. To refer to the full circumference, you can multiply the value by 2 (see "Approx. Underbust Circumference" in the table above). All measurements are taken from the garment laid flat.

When measuring, customers should use a soft tape measure to wrap around their underbust area (below the bust, snugly against the ribs), keeping it level and slightly taut, to get their underbust measurement. Size 9 is more suitable for an underbust of approximately 66–74cm and cup size A–B; Size 11 is more suitable for an underbust of approximately 72–80cm and cup size B–C.

This style features an underwire design with adjustable back straps/panels, providing approximately 6cm of adjustment space to accommodate minor size differences. If you are between two sizes: for a snugger fit and more concentrated support, choose the smaller size; if your bust is fuller, you are concerned about compression, or prefer more coverage, it is recommended to choose the larger size and then fine-tune with the back straps and panel for more comfortable and secure wear.