Field Changeable Fiber Optic Connector Polarity Keying

A combination of an adapter and a multi-fiber fiber optic connector, the combination comprising:

• the multi-fiber fiber optic connector having an inner housing surrounded at least partially by an outer housing, and a key attached to the inner housing, the key having a cantilevered portion extending from a central portion towards a front end of the key;
• and
• the adapter having an opening to receive the multi-fiber fiber optic connector in a correct orientation of the key, the opening having a surface facing away from the adapter,
• wherein the cantilevered portion has a latch with an adapter engagement surface configured to engage the surface of the adapter facing away from the adapter when the key is in an incorrect orientation, thereby preventing an incorrect polarity insertion of the fiber optic connector into the adapter.