A board or panel can mean a few different types of surfaces when used. Boards can have a cardstock or paper-type working surface that has a backing of some sort - either heavier cardboard, wood, or usually means a working surface that has a backing of some sort - heavier cardboard, thin wood or hardboard. Claybord or Aquabord have a clay working surface. And wood panels are made from different types of wood.
Illustration board is also manufactured as hot pressed or cold pressed. While the cold pressed illustration board is comparable to bristol vellum, the backside has a heavy board for support so only one side of the board can be used.
Ampersand claybord is made out of kaolin clay sanded smooth on an aspen wood hardboard. It is archival, eco-friendly and formaldehyde-free.
Ampersand Aquabord is an archival, acid-free textured clay surface that absorbs watercolors like a fine paper. It does not require stretching and will not tear, shrink or buckle.
Wood is another surface that works well with colored pencil. Panels come in a variety of wood and can be primed/gessoed