Nostalgie Hard-Cover Sketch Books by Hahnemuhle feature heavy-weight 90 lb. (190 gsm), natural white, acid-free and high longevity paper. The flexible and fine grain paper allows for control and is ideal for all dry-painting techniques as well as wet colors. Each book is solidly thread-bound to provide flatness of sheets. Book is hard-wearing and nice to the touch with an anthracite-colored cover and linen structure. 40 sheets (80 page)s per book.