The four sides of Crester Watercolor paper are hardened with a thin glue, so there is no need to be watered and the paper will not move when drawing.
Each sheet is perforated with a paper knife.
Size: L 15.0 x 11.0 inches (380 x 280 mm); Inner Paper 10.1 oz (310 g) (Extra Thick), Medium Grade, 16 Sheets; Block Type: Quarter Glue.
(From Amazon.co.jp)