From the manufacturer:
Our recycled, heavyweight sketch is a hard, clean sheet with excellent erasing qualities. The elemental chlorine free sheet has 30% post-consumer waste recycled fiber and meets the U.S. government standards for a recycled sheet. Pads are double wire, side binding and micro perfed for easy sheet removal.
ACID FREE
Weight: 70 lb. (114 g/m2)
Color: Natural white
Surface: Clean
Media: Pencil, pen and ink, crayon, chalk, charcoal, and paste