A card edge connector includes a longitudinal insulative housing, a number of terminals retained in the insulative housing, a pair of transparent members mounted to the insulative housing, and a metallic shell surrounding around the insulative housing. The insulative housing has two side walls extending along a longitudinal direction, two end walls connecting between the longitudinal ends of the two side walls and a center slot defined therebetween. The metallic shell includes two covering portions respectively located above the two side walls in a vertical direction perpendicular to the longitudinal direction. Each of the covering portions has a number of through-holes arranged above the transparent members to leak out the light transferred therefrom.