What is the smallest detectable object for F3SN series Safety Light Curtain?

The smallest detectable object is one of a size that will always break the Safety Light Curtain beam at any point in the Safety Light Curtain protective height. 

Specifically, the smallest detectable object is a non-transparent object as big as the optical axis pitch plus the lens diameter, as shown in the following diagram that will break the beam at any point (position). 

F3SN-A[][][][]P14 (Optical axis pitch: 9 mm, Smallest detectable object: 14 mm dia.)