Found An Eberhard Faber Mechanical Pencil

[Knoob]

I found this mechanical pencil a couple years ago , tried to look into it and found nothing .

Last week i saw it in my drawer and decided to investigate , noticed it had 4 slots for lead and it has D.R.P inscripition near the tip and Eberhard Faber on the top, the top also unscrews to reveal an eraser .

 

I wanted to know where to get lead reffils (i think its 1.8mm not sure) and how much it would go for.

Thank you very much