The purpose of the phantoms is the generation of correction matrices and the performance of regular constancy tests of the system inhomogeneity, the most important parameter for quality control of gamma cameras. The flood phantoms of the FP series are available in various dimensions for different detector sizes. They have some unique features for measuring precisely, saving time and protecting users against radiation exposition: The cuvette wall thickness of 20 mm and a defined extension volume ensure stable geometry and high measuring precision when using the filled phantom.