This part is a kind of semiconductor called STR-4A60S.

Function of this product has Sensitive Gate Triacs.

Manufacturers : TGS

Image and pinout :

Some of the text within the PDF file :

TIGER ELECTRONIC CO.,LTD Product specification Sensitive Gate Triacs STR4A60S GENERAL DESCRIPTION This device is sensitive gate triac suitable for direct coupling to TTL, HTL, CMOS and application such as various logic functions, low power AC switching applications, such as fan speed, small light controllers and home appliance equipment. ABSOLUTE MAXIMUM RATINGS ( Ta = 25℃ ) Parameter Symbol Typ Unit Repetitive peak off-state voltages RMS on-state current Non-repetitive peak on-state current Max. Operating Junction Temperature Storage Temperature VVDRRRMM IT(RMS) ITSM 600 4.0 30 V A A Tj 110 ℃ Tstg -45~150 ℃ TO-126 ELECTRICAL CHARACTERISTICS ( Ta = 25℃ ) Parameter Symbol Test Conditions Min Typ Max Unit Repetitive peak off-state voltages VVDRRRMM 600 V [ ... ]

STR-4A60S PDF Datasheet Download