The QA-ST is designed to quickly check electrical safety on medical and industrial devices. It is palm-sized and very portable. The tests can be performed manually or in step-by-step mode. The results are displayed in a bright 4-digit LCD display. The QA-ST performs all electrical safety tests necessary to satisfy AAMI ESI, NFPA-99, VDE 701, VDE 751 and HEI 95. It also features differential current measurements obtained by an internal current clamp. This presents a new leakage current measurement technique for convenient testing of medical equipment with a fixed power cord (hardwired to wall, not detachable).