A connector of horizontal construction includes at least a pair of first and second halves that are mated together along a common mating line. A plurality of mating blades are supported in a vertical arrangement within a mating portion of the connector. The connector includes two distinct fastenings means for holding the housing halves together. A first fastening means is provided as a horizontal attachment member that extends widthwise in the mating portion in a space between the circuit cards. A second fastening means is provided as an exterior retainer that engages at least part of the outer circumference, or perimeter of the connector.