How can I open files with the extension .ef?

What are the ways to open files with .pk extension?

• How to open file with .pk extension? Is there any way to open this file using an online software? What are the (free) software available on the internet that can open these files? Is there any (free) software to convert files with '.pk' extension to '.html/.htm/.pdf' extension?

• Answer:

  Adobe Systems Incorporated acquired the technology  assets of Syntrillium Software in May 2003. On August 18th, 2003 Adobe  released a rebranded version of Cool Edit Pro 2.1 as Adobe Audition  software. Audition/Cool Edit creates .PK files which are known as Peak  Files. Peak files store data associated with the graphical  representation of audio data (i.e., Waveform diagram). Audition/Cool  Edit has the option to disable the creation of these files, however this  may slow loading, saving and re-drawing of graphical data. These files  can safely be deleted and will not effect the original audio data in any  way. .....               Source(s):         http://filext.com/file-extension/PK