The medium wallet is roughly 4x4.5 inches. The medium wallet sketchbooks are roughly 3.5 inches square and are great to draw or write in. Everybody loves to draw or take notes on Post-It Notes and these books are larger than those, plus the square format is great for posting to Instagram :-) This wallet includes 5 RFID protected card slots, a money pocket across the top like a traditional wallet and an elastic loop to hold a pencil. These classy and rugged genuine leather wallets come in black or brown and is the perfect pocket-sized sketchbook for drawing on the go.