Special Clairefontaine Herbarium Block 21x29.7cm Ideal block to collect your favorite plants and flowers. Includes a thin sheet of glassine sandwiched between sheets of heavy duty paper. This will keep your flowers and plants better. You can also draw and write on thick paper with markers, crayons, pencils... Ideal for educational activities abroad. The 32 sheets are bound together with a gold spiral for ease of use. Size: 21 x 29.7cm (A4) Thick sheet weight: 180 g Fine sheet grammage: 37 g It is made without acid and is PH neutral. Brand: Clairefontaine