This is a 5.0V unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Polytronics. It has a maximum clamping voltage of 53.3V, a peak pulsed reverse voltage of 36.7V, and a continuous reverse voltage of 33V. The diode is packaged in a Surface Mount Device (SMC) DO-214AB and is compliant with the Restriction of Hazardous Substances (RoHS) directive.