Have you considered when writing out your research with a normal ink pen how it will fade and deteriorate in a very short time dependent upon storage of the documents?
Using an acid free pen ensures your valuable research lasts the test of time and can be passed on to future generations.
All are of archival quality and give you plenty of scope for colour coding family tree charts and trees, or can be used for adding highlights to notes for your permanent records. Also useful for writing notes to friends, on greeting cards and for general and craft use.
NB. You need to use acid free paper or card with the pen to ensure longevity.