This part is a kind of semiconductor called BTA10.

Function of this product has logic level and standard Triacs.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

BTA10, BTB10, T10xx 10 A SnubberlessTM, logic level and standard Triacs Datasheet - production data Features  Medium current triac  Low thermal resistance with clip bonding  Low thermal resistance insulation ceramic for insulated BTA  High commutation (4Q) or very high commutation (3Q, Snubberless™) capability  BTA series UL1557 certified (file ref: 81734)  Packages are RoHS (2002/95/EC) compliant Description Available either in through-hole or surface mount packages, the BTA10, BTB10 and T10xx Triac series are suitable for general purpose mains power AC switching. They can be used as ON/OFF function in applications such as static relays, heating regulation or induction motor starting circuit. They are also recommended for phase control operations in light dimmers a [ ... ]

BTA10 PDF Datasheet Download