This is Koh-i-noor All Metal 5.6mm Lead Holder with Sharpener 5359 : Silver
This is a mechanical pencil, all metal with a clip. it is used for common writing anddrawing with lead of 5,6 mm in diameter.
The lead is moved by pressing the sharpener knob in leaned pencil position, which opens the clamp and the lead slides out. The lead can be sharpened and the sharpener is located in the knob that is to be screwed out.