This part is a kind of semiconductor called BC817-16.

Function of this product has 45V NPN SMALL SIGNAL TRANSISTOR IN SOT23.

Manufacturers : Diodes Incorporated

Image and pinout :

Some of the text within the PDF file :

Features  Ideally Suited for Automatic Insertion  Epitaxial Planar Die Construction  Complementary PNP Types Available (BC807)  For switching and AF Amplifier Applications  Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)  Halogen and Antimony Free. "Green" Device (Note 3)  Qualified to AEC-Q101 Standards for High Reliability  PPAP Capable (Note 4) SOT23 BC817-16/-25/-40 45V NPN SMALL SIGNAL TRANSISTOR IN SOT23 Mechanical Data  Case: SOT23  Case Material: Molded Plastic, “Green” Molding Compound; UL Flammability Classification Rating 94V-0  Moisture Sensitivity: Level 1 per J-STD-020  Terminals: Finish – Matte Tin Plated Leads, Solderable per MIL-STD-202, Method 208  Weight 0.008 grams (Approximate) Top View Device Symbol Top View Pin- [ ... ]

BC817-16 PDF Datasheet Download