Simple and easy to use. Drag and drop files to the "Open All Files" window to view file contents. I had success with PDF, Word DOC & DOCX, Excel, PowerPoint PPT & PPTX (scroll and view all slides), JPG, RAW, GIF, PNG, ICS, PAGES, ODT, TAR, TXT, TIFF, ZIP, RTF, MOV (playable), m4a (playable), mp4 (playable), mp3 (playable). Whislt some files are not designed to be viewed the application recognized certain file types even if it cannot view them. Sure there are some proprietary file types like Visio VSDX or other Visio template files, that it is not currently capable of displaying but for the most part this is an awesome little viewer that can be used in a pinch to view almost anything. Obviously with some caveats of course, it can’t view absolutely everything biut does most everyday files you will likely use apart from some specific applications. Having tried and used many viewer apps on multiple platforms I can say that this utility is a gem worth having on your system. I’m impressed with its capabilities.