Staedtler 316 Lumocolor WP8 Universal pen F-tip, about 0.6 mm, non-permanent, 8 pieces in tiltable Staedtler Box (Office supplies & stationery)
What can I say. There are easily removable pins. For my purposes, they can even stay a few days on its lower surface and can be easily removed yet. But if you expose the color of the light and the heat, then it should be as soon as possible removed,