Stillman & Birn Epsilon Series Softcover Sketchbook, 8" x 10", 150 GSM (Heavyweight), White Paper, Smooth SurfaceHEAVYWEIGHT PAPER: Strong enough to use wet media on both sides of page. Great for fine line artwork and technical drawing with ink wash. CRAFTED FOR MIXED MEDIA: Double sized (from non animal materials) for enhanced wet strength and glowing color. ERASABLE & TOUGH: Withstands multiple erasures and holds up well to layered light washes of wet media. DURABLE: Premium U. S. sewn binding, deluxe covers and heavy duty art paper equals a sketchbook that is