An electrical connector system comprising: a header connector comprising a header housing and a header contact, the header housing comprising a header base and a header shroud extending from the header base, the header base comprising a header contact opening, the header contact being held by the header base within the header contact opening; and a receptacle connector configured to mate with the header connector, the receptacle connector comprising a receptacle housing and a receptacle contact that engages the header contact when the header and receptacle connectors (14, 12) are mated together, the receptacle housing comprising a receptacle base and a receptacle shroud extending from the receptacle base, the receptacle base comprising a receptacle contact opening, the receptacle contact being held by the receptacle base within the receptacle contact opening, wherein the receptacle contact opening has a common size and shape to the header contact opening, wherein the header contact comprises header contacts, the receptacle contact comprises receptacle contacts, and each receptacle contact engages a corresponding header contact when the header and receptacle connectors (14, 12) are mated together, characterized in that the header base and the receptacle base each comprise a mounting side configured to be mounted on a printed circuit board, and the header opening comprises header openings, each header contact being held within a corresponding one of the header openings, and the receptacle opening comprises receptacle openings, each receptacle contact being held within a corresponding one of the receptacle openings, wherein the receptacle and header contact openings that hold corresponding header and receptacle contacts (66, 64) have a common size and shape relative to each other. a header connector comprising a header housing and a header contact, the header housing comprising a header base and a header shroud extending from the header base, the header base comprising a header contact opening, the header contact being held by the header base within the header contact opening; and a receptacle connector configured to mate with the header connector, the receptacle connector comprising a receptacle housing and a receptacle contact that engages the header contact when the header and receptacle connectors (14, 12) are mated together, the receptacle housing comprising a receptacle base and a receptacle shroud extending from the receptacle base, the receptacle base comprising a receptacle contact opening, the receptacle contact being held by the receptacle base within the receptacle contact opening, wherein the receptacle contact opening has a common size and shape to the header contact opening, wherein the header contact comprises header contacts, the receptacle contact comprises receptacle contacts, and each receptacle contact engages a corresponding header contact when the header and receptacle connectors (14, 12) are mated together, characterized in that the header base and the receptacle base each comprise a mounting side configured to be mounted on a printed circuit board, and the header opening comprises header openings, each header contact being held within a corresponding one of the header openings, and the receptacle opening comprises receptacle openings, each receptacle contact being held within a corresponding one of the receptacle openings, wherein the receptacle and header contact openings that hold corresponding header and receptacle contacts (66, 64) have a common size and shape relative to each other.