Stillman & Birn Zeta Softcover Sketchbook, Heavyweight 180lb, White, 28 Sheets, 3.5X5.5 Contains 28 sheets of extra heavy-weight 180lb archival paper The paper is white and has a smooth surface Suitable for all dry media as well as light washes-wet media-watercolor ph neutral as well as lignin and chlorine free Flexible yet rugged soft-bound cover with sewn bindings