Circuit Protection Devices, Triac circuits, Thyristor circuit, protector breaker

 T410 Series 600 Vdrm 4 A Surface Mount Logic Level Triac AC Switch - TO-252

https://www.futureelectronics.com/p/electromechanical--circuit-protection--power-thyristors/t410-600b-tr-stmicroelectronics-2124375