I've taken photos of each cover and inner pages for your reference. Here are the details: Vacuum Technology themed: 24.5*16.5 cm; Bunny themed: 20.5*14 cm; Plain colored: 18.2*13.2 cm; EF branded: cover size 18.7*12 cm, two available; The last one: 20*13.5 cm, it's relatively thin. If you buy all together, it's 30 yuan with free shipping. All items are brand new and unused. Feel free to reach out if you're interested!