This part is a kind of semiconductor called BTB16-800BW.
Function of this product has 16A TRIACS.
Manufacturers : TGS
Image and pinout :

Some of the text within the PDF file :
TIGER ELECTRONIC CO.,LTD Product specification 16A TRIACS GENERAL DESCRIPTION BTA/BTB16-800BW Available either in through-hole or surface-mount packages, the BTA/BTB16 - 800BW 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 series) are specially recommended for use on inductive loads, thanks to their high commutation performances. By using an internal ceramic pad, the BTA series provides voltage insulated tab (rated at 2500V RMS) complying with UL standards. ABSOLUTE MAXIMUM RATINGS ( Ta = 25 C) PARAMETER Repetitive peak off-sta [ ... ]
BTB16-800BW PDF Datasheet Download
