This part is a kind of semiconductor called EER28.

Function of this product has EER Series Bobbins.

Manufacturers : JFE

Image and pinout :

Some of the text within the PDF file :

FERRITE CORES FOR POWER SUPPLY Bobbins for EER and EIR Cores E øD H F J H øD E C F J B L B L A P1 P1 P1 P1 P1 P1 P1 P1 P1 P1 ød P0 ød P0 G C ø ø 16 A G [ ... ]

EER28 PDF Datasheet Download