A vaginal speculum with a blade size of 20 x 70 mm (or 70 x 20 mm, where the numbers indicate length and width) is a specific, small-to-very-narrow instrument.

This device has a tube size of Ø20x70 mm . It is described as an "F.O. Anoscope" with an obturator, meaning it is not a typical bivalve speculum but rather a cylindrical device.