The fracture strength and processing ability of glass and plastic products are strongly determined by internal mechanical stresses. But even small residual stresses influence the optical properties, an undesirable effect in many applications, e.g. lenses for microlithography. Therefore, constant testing of residual stress is a very important part of development and quality control. The StrainMatic series of imaging polarimeters automates the measurement and evaluation of the stress birefringence and enables a fast and exact determination of residual stresses and their spatial distribution. The solid and robust housing made out of bended, 4 mm thick aluminum plates seizes the straight corporate design of the manufacturer and veils the complex technical interior in the smallest space. The vertically sliding door completely disappears in the housing in open state and enables an optimum access to the sample compartment. A mechanical mechanism hidden in the interior always keeps the door in balance, so that only a minimum exertion of force is necessary to operate the door.