An electrical connector (100) comprises a first insulative housing (10), a second insulative housing (30) engaging with the first insulative housing (10), and a plurality of contacts. Said second insulative housing (30) has a first platform (321) and a second platform (322) arranged at different levels. Each of the contacts (20) includes a mating portion (21) supported by the first insulative housing and a tail portion (23) supported by the second insulative housing, the tail portions (23) of the contacts are spaced into two rows and located on the first and second platforms; another contact has a tail portion disposed inside the second insulative housing.