Series 400 Bristol generally describes drawing paper that is pasted together to form multi-ply sheets.

A high quality multi-ply bristol. 15 sheets, 2 ply(100lb. / 270g/m²), Acid-free

Smooth finish is excellent for fine line drawings using pen & ink or marker.

Vellum finish is excellent for pencil, charcoal, and pastel, as well as airbrush and light washes. Not recommended for traditional watercolor techniques.