This is a multifunctional, precision quality assurance tool for daily, weekly or monthly quality assessments of all mechanical and geometrical treatment parameters of linear accelerators or teletherapy units. It is designed to easily and accurately check collimator isocentricity, gantry isocentricity, table isocentricity, collimator field size accuracy, radiation/light field congruence, isocenter rotational stability, ODI accuracy and laser light alignments.