Omnichrom Pencil contains water soluble lead so you can add opaque markings to various dark or light surfaces.

• Used on a range of surfaces including plastic, glass, metal, leather, lacquer and more
• The lead is water soluble and can be wiped away or washed out 

These pencils are perfect for students who need to write on Microscope Slides or X-ray Films.

(note these pencils DO NOT write on your skin)