MTRJ style:
This connector is radically different than the other connectors shown, in large part, due to the single ferrule that handles two fibers. This is the first of the Small Form Factor (SFF) connector designs to reach a measure of market acceptance. The MT-RJ is a variation of the reliable MT-ferrule connector series, the first major multi-fiber ferrule design.

(Please note the dust caps on the connector tips. They are there for the protection of the fiber in the ferrules.)