A card edge connector includes an elongated housing with a pair of latches disposed at opposite ends thereof and defining a mating groove in the housing and between said pair of latches. A first wall and a second wall are formed at opposite sides of the mating groove, on which a plurality of conductive terminals are mounted. A key protrudes into the mating groove from the first wall with a distal end sinking into the second such that the second wall can be molded in an uninterrupted manner without the joint of the key.