Cellulose Acetate is a material originally used for things like video tapes and other applications where the extreme flammability of celluloid was a danger for general safety. It allows for a large amount of unique color combinations. It is super nice to machine and polishes up to a great, great shine.
The pen will be made out of the exact blank seen in the pictures. However, the inside will be very very different than the outside. Like opening a treasure chest! These blanks are fairly large, so they allow for the full range of sizes we have.