A. If you have a MacBook:
11.6 Inch MacBook Air - - - Choose the 11" size
12 Inch New MacBook - - - Choose the 12" size
13.3 Inch MacBook Air/Pro - - - Choose the 13" size
15.4 Inch MacBook Pro - - - Choose the 15" size
The design is a snug fit for MacBook(Model before 2017), slightly loose-fitting for 2017 New Model.Notice that if you need a snug fit, please make sure dimensions of your laptop are very close to the internal dimensions of the model you choose
B. If you have the iPad, Surface Pro, Surface Laptop, Dell, HP, Lenovo, ThinkPad, Samsung, Acer, Asus etc:
Please choose the correct size according to your Laptop's Dimensions rather than your Laptop/Tablet's Screen Size. And make sure the internal dimensions of your laptop is smaller than the laptop sleeve's size you choose, the more similar, the more perfect!
C: There may be some creases or lines on the PU leather surface when you receive it and use it. Don't worry about this, it's not damaged.