An electrical connector (100) includes: an insulative housing having a base (11) and a pair of side walls (12), each side wall having a resilient inner arm (121) and a stationary outer arm (122); and plural contacts (2) retained to the insulative housing, wherein the resilient inner arm extends along a horizontal, front-to-back direction and has a front end operable in both a vertical, top-to-bottom direction and the horizontal, front-to-back direction to move toward the stationary outer arm.