This part is a kind of semiconductor called BTA08-600BW.

Function of this product has logic level and standard 8A Triacs.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

BTA08, BTB08, T810, T835, T850 Snubberless™, logic level and standard 8 A Triacs Datasheet - production data Features  On-state rms current, IT(RMS) 8 A  Repetitive peak off-state voltage, VDRM / VRRM 600 V to 800 V  Triggering gate current, IGT (Q1) 5 to 50 mA Description Available either in through-hole and surfacemount packages, these devices are 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 and motor speed controllers, etc. The Snubberless versions (BTA, BTB08_xxxxW and T8 series) are specially recommended for use on inductive loads, thanks to their high commutation performance. Logic level versions a [ ... ]

BTA08-600BW PDF Datasheet Download