MEDIUM: Can fit a water bottle, snacks, a book, wallet, sunglasses and a 13” Macbook snugly. RETAILS: $132 Measurements; 11.5” wide across the bottom 15” wide across the top 5.5” deep 12” tall. Pocket Measurements: Interior pocket: 5.5" High x 8.25" Wide Exterior pocket: 7" High x 10" Top Width x 8.75" Bottom Width