The P6KE220A with Unidirectional DO-15 TVS ROHS is a type of Transient Voltage Suppressor (TVS) Diode manufactured by Liown. It is designed to protect against high voltage transients such as electrostatic discharge (ESD). It is unidirectional, meaning that it only conducts current in one direction, and is rated at 1.9A, 1uA, 600W for 328V, 209V, 185V, and 231V respectively. The device is RoHS compliant, meaning that it does not contain lead or other hazardous substances.