This is one of the semiconductor types. This part name is C4558.
This product has 2SC4558 functions.
Manufacturers of product is Sanken Electric.
Image and pinout :
C4558 PDF Datasheet
Some of the text files within the PDF file
Silicon NPN Triple Diffused Planar
1. High hFE and Low Vce(sat) Transistor
Application Example : Series Regulator, Solenoid Driver, and General Purpose
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Please refer to the file for details.