If you are looking at the MD-PL100 series circular connectors from CUI, you may see a small notch on the metal ring inside the housing.
Confirmed by the manufacturer, the image on the datasheet is for illustration only. Actually, this little notch isn’t called out or specified in the datasheet drawing. The orientation of this notch may be not same as the image; this is not considered a product defect.
Applicable Part Numbers
MD-30PL100
MD-40PL100
MD-50PL100
MD-60PL100
MD-80PL100
CP-2930-ND
CP-2940-ND
CP-2950-ND
CP-2960-ND
CP-2980-ND