Smile Windows is a free Chrome add-on developed by ONEO that allows users to open the current webpage in a new window with specified device size. With this add-on, users can easily pop up a new window, which will display the current page in the size of their choice.

This add-on is especially useful for web developers and designers who need to test the responsiveness and layout of their websites on different device sizes. By simply clicking on the Smile Windows icon in the Chrome toolbar, users can instantly open a new window with the specified dimensions and view the current page in the selected size.

Smile Windows provides a convenient and efficient way to preview webpages in various device sizes, helping developers and designers ensure that their websites look great on all screens. It is a valuable tool for anyone involved in web development and design.