This part is a kind of semiconductor called BTA12-800CW.

Function of this product has 12A TRIACS.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

® BTA/BTB12 and T12 Series 12A TRIACS SNUBBERLESS™, LOGIC LEVEL & STANDARD MAIN FEATURES: Symbol IT(RMS) VDRM/VRRM IGT (Q ) 1 Value 12 600 and 800 5 to 50 Unit A V mA A1 G A2 A1 A2 DESCRIPTION Available either in through-hole or surface-mount packages, the BTA/BTB12 and T12 triac series is suitable for general purpose AC switching. They can be used as an ON/OFF function in applications such as static relays, heating regulation, induction motor starting circuits... or for phase control operation in light dimmers, motor speed controllers,... The snubberless versions (BTA/BTB...W and T12 series) are specially recommended for use on inductive loads, thanks to their high commutation performances. Logic level versions are designed to interface directly with low power drivers such as mi [ ... ]

BTA12-800CW PDF Datasheet Download