K1 Screw hotend

Hello,
I have a problem: the screw that holds the hotend on my K1 has its thread slightly damaged, and I would like to replace it. Do you know the reference for this screw, or do I need to replace the whole heatsink to get it?
The screw I measured is about 23 mm long including the head, with a diameter of about 3 mm at the head, but the threaded part seems to be only 2 mm.

Is the heat sink thread stuff or fasteners?