United Kingdom Size Regular to US: Ultra

United Kingdom Size Regular: Corresponds to a Syngina fluid capacity range of 6–9 $\text{g}$, FDA absorbency tier of Regular Absorbency (6 to 9g), EDANA classification Normal / Medium (6 to 9g), physical dry dimensions of 48 $\text{mm}$ length $\text{x}$ 13 $\text{mm}$ dia., recommended flow Light to Moderate Flow, and format type Digital / Standard Applicator.

US: Ultra: Corresponds to a Syngina fluid capacity range of 15–18 $\text{g}$, FDA absorbency tier of Ultra Absorbency (15 to 18g), EDANA classification Ultra / Maximum (15 to 18g), physical dry dimensions of 55 $\text{mm}$ length $\text{x}$ 18 $\text{mm}$ dia., recommended flow Very Heavy Flow / Overnight Protection, and format type Digital / High-Density Core Applicator.