The determination of the velocity in a single plane often does not yield enough information to answer fluid-mechanical questions. To enable the simultaneous determination of all 3D velocity and vorticity components or acceleration fields a dual plane stereo setup is used. This system consists of two double-pulse lasers with orthogonally linearly polarized light and 4 cameras with appropriate filters. It can be seen as two 3D (Stereo) systems at the same time but each looking at particles in a different plane. The polarized light and the filters on the cameras assure that each camera images only one of the two adjacent planes.