S=Dark Color 2 B5,M=Light Color B5. Size: B5, 9.8 x 6.9 inches (25 x 17.6 cm), 7 mm college ruled pages. Colors: 4 colors including black, purple, dark green and red, one piece each, total 4 pieces. Cover: thick plastic hardcover, waterproof. Paper: 80 gsm thickened paper, 80 sheets/160 pages, double-sided writing with no bleed-through. Purpose: suitable for study, work, notes, office, homework, travel, suitable for all ages. Weight: 3.06 pounds.