An electrical connector includes an insulative housing defining a base and a cover confronting with the base, and a plurality of contacts sandwiched between the base and the cover. The base defining at least one latching post to engaging with corresponding mating hole on the cover. The at least one post is a cone tubular with a diameter of a free end thereof larger than a diameter of a root thereof and the mating hole has a portion aligned with the free end which has a larger diameter than another portion thereof aligned with the root.