The BTA204S-600B,118 is a two-way thyristor (TRIAC) manufactured by WeEn Semiconductors. It has a 600V blocking voltage and is housed in a TO-252-3 RoHS package. This thyristor is bidirectional, meaning it can conduct current in either direction, and is designed for use in AC applications. It is typically used in load control and phase control applications, such as motor speed control, thermal control and dimming of lighting systems. The device has a current rating of 4A RMS and is RoHS compliant, making it suitable for high reliability applications.