An electrical connector includes a contact module enclosed within a pair of over-molding covers. The contact module includes one row of contacts retained in an insulator via an insert-molding process. Each cover includes a rear base part and a front tongue part extending forwardly from the base part. Each contact has a front contacting section exposed upon the tongue in a vertical direction, and a rear tail section exposed outside of the base. The contacts are exposed upon only one tongue part in the vertical direction.