The QP12W05S-37A is an insulated gate bipolar transistor (IGBT) through hole part manufactured by MORNSUN. It is RoHS compliant, meaning that it contains no hazardous materials, and is lead-free. It has a working voltage of 600 volts, a maximum current of 12 amperes, and a collector-emitter saturation voltage of 2.0 volts. It is designed for use in power converting circuits, and the datasheet provides more information on the performance of the part.