This part is a kind of semiconductor called BTB16.

Function of this product has 16A TRIACS.

Manufacturers : UTC

Image and pinout :

Some of the text within the PDF file :

UNISONIC TECHNOLOGIES CO., LTD BTB16 Preliminary 16A TRIACS  DESCRIPTION The UTC BTB16 is a 16A triacs which can be operated in 4 quadrants, it uses UTC’s advanced technology to provide customers with high commutation performances. The UTC BTB16 is suitable for AC switching application and phase control application such as fan speed and temperature modulation control, lighting control and static switching relay, either in through-hole or surface-mount packages.  SYMBOL TRIAC  ORDERING INFORMATION Ordering Number Lead Free Halogen Free BTB16L-x-x-TA3-T BTB16G-x-x-TA3-T Package TO-220 Pin Assignment 123 MT1 MT2 G Packing Tube  SENSITIVITY AND TYPE PART NUMBER B C ◎: Available  MARKING VOLTAGE 600V 800V ◎◎ ◎ SENSITIVITY 50mA 25mA TYPE STANDARD S [ ... ]

BTB16 PDF Datasheet Download