Abstract: A fiber optic connector assembly for mating an optical fiber to a receptacle includes an adapter and a plug separably coupled to the adapter. The adapter has a first end coupled to the receptacle with a first surface of the adapter contacting a surface of a housing wall through which the receptacle projects. A sealing member is disposed between the first surface of the adapter and the surface of the housing wall. In one embodiment the sealing member includes an O-ring groove provided in the first surface of the adapter and an O-ring disposed in the O-ring groove. The plug has an external surface with an alignment band formed on the external surface thereof. A first end of the plug is separably coupled to the second end of the adapter and a second end of the plug is adapted to receive the optical fiber. The connector assembly further includes a locking mechanism to prevent the plug from separating from the adapter in response to a vibration force.