An electrical connector includes an insulative housing and a plurality of contacts retained therein. The housing forms a central slot along a longitudinal direction, and includes a base, opposite first wall and second wall extending from the base and located by two sides of the central slot. The contact includes a retaining section retained to the corresponding first or second wall, and a spring arm with a contacting section at a free end, extending from the retaining section and into the central slot wherein a width/thickness ratio in the contacting section is set within a range between 0.8˜1.28.