pencil kits

Lurking for several months, but this is my first post. Does anyone know if pencil kits are available with 0.3 mm or 0.5 mm pencil leads? So far, all I have found is 0.7 mm and up.

I have been making pens for about a year now and have purchased all my kits from WoodTurningZ. For the most part I have been happy, but have had some concerns with the slimlines. I have found that the black ink is normally terrible (blotchy) - not the quality I would want wen selling them...