This part is a kind of semiconductor called BTA40.

Function of this product has 40A STANDARD TRIAC.

Manufacturers : Unisonic Technologies

Image and pinout :

Some of the text within the PDF file :

UNISONIC TECHNOLOGIES CO., LTD BTA40 Preliminary 40A STANDARD TRIAC  DESCRIPTION The UTC BTA40 is a 40A standard triac, it uses UTC’s advanced technology to provide customers with low thermal resistance with clip bonding and high commutation capability, etc. The UTC BTA40 is suitable for general purpose AC switching, heating regulation and on/off function in static relays, etc.  FEATURES * Low thermal resistance with clip bonding * High current capability * High commutation capability  SYMBOL TRIAC  ORDERING INFORMATION Ordering Number Lead Free Halogen Free BTA40L-x-x-T47-T BTA40G-x-x-T47-T Package TO-247 Pin Assignment 123 MT1 MT2 G Packing Tube  SENSITIVITY AND TYPE PART NUMBER B ◎: Available VOLTAGE 600V 800V ◎◎  MARKING SENSITIVITY 50mA [ ... ]

BTA40 PDF Datasheet Download