An electrical connector (100) includes an insulative housing (1), a plurality of terminals (2), a metal plate (3), a first metallic shell (4) and a second metallic shell (5). The first metallic shell has a pair of side walls (43). The second metallic shell includes a pair of side boards (52). Each side wall has a first portion (4301), a second portion (4302), an elastic fin (431) extending from the first portion and a first angle relative to the second portion. Each side board defines a window (521) and the elastic fin protrudes into the window and resists against a contour of the window at a plurality of resisting points (4321) for prohibiting a relative movement of the first metallic shell, with respect to the second metallic shell. Each elastic fin is located in a vertical plane and the degree of the first angle is between 0 and 90°.