Electrical connector assembly

An electrical connector assembly, comprising:

• a first connector comprising a first housing, the first housing comprising:
• a complementary connector receiving concavity;
• a first contact attached to the first housing;
• a first connector projection extending in a connector mating direction, the first connector projection formed on an inside of a lower wall and comprising a protruding part that is provided at the top of the first connector projection and that protrudes in a horizontal direction substantially perpendicular to the connector mating direction;
• and
• a first connector concavity formed on an inside of a side wall of the complementary connector receiving cavity and extends in the connector mating direction and is recessed in a direction substantially perpendicular to the connector mating direction;
• and
• a complementary connector that mates with the first connector, the complementary connector comprising a complementary housing received by the complementary connector receiving concavity, the complementary housing comprising:
• a complementary contact attached to the complementary housing;
• a groove formed in an undersurface of the complementary housing and having a cross-sectional shape that is complementary to a cross-sectional shape of the first connector projection and extending in the connector mating direction;
• and
• a side projection provided on a side surface of the complementary housing and extending in the connector mating direction, the side projection having a cross-sectional shape that is complementary to a cross-sectional shape of the first connector concavity;
• wherein displacement of the complementary housing with respect to the first housing in a vertical direction is restricted by the first connector projection being received in the groove and by the side projection being received in the first connector concavity.