A connector (101) adapted for mounting to a panel (200), includes an insulative housing (1) having a mating portion (12), a mounting portion (13) extending rearward from the mating portion, at least a lock tab (132) formed on a top or a bottom surface of the mating portion and disposed adjacent to the mounting portion; at least a retainer member (15) connected to a lateral side of the insulative housing, said retainer member having a passageway extending along a front-to-back direction, and an aperture (1521) defined in the retainer member (15) and communicating with the passageway; a slider member (5) including a main portion accommodated in the passageway of the retainer member, said main portion defining a cavity portion (542) with an inclined back side; a spring member (6) received in the passageway and capable of pushing the main portion sliding forwardly to reach a lateral side of the mounting portion; and a pusher member (7) having a finger portion extending into the cavity portion via the aperture of the retainer member and capable of pressing onto and sliding along the inclined back side to urge the slider member movement rearward.