dilator, traditionally used by the gynae-cologist for dilatation of the cervix, has been used in the past by the urologist for dilatation of the female urethra and corpus cavernosum prior to insertion of a penile pros- thesis. The size of a Hegar dilator is measured by the diameter, with units of millimeters (mm) and can be between 1 mm and 26 mm in diameter. Pratt dilators are usually measured using the French Scale system.