A card reader is positioned in a housing that has length, height and width dimensions. The read head is configured to be coupled to a mobile device and has a slot for swiping a magnetic stripe of a card. The read head reads data on the magnetic stripe and produces a signal indicative of data stored on the magnetic stripe. The read head has length, height and width edge surfaces. An asymmetric spring is coupled to the read head. The asymmetric spring positions the read head to be offset in the housing with the housing length and height edges being non-symmetrical in respect to the length and height edges of the read head. An output jack is adapted to be inserted in a port of the mobile device and deliver an output jack signal to the mobile device.