This is an audio file for use with the Pomodoro Technique for time management and work productivity - it plays twenty-five minutes of a ticking sound, ending with an alarm, followed by five minutes of silence. The basic idea is that you work solidly for twenty-five minutes, then take a five minute break, and you chalk that up as "one pomodoro". At the end of the day, you have an unambiguous tally of how much actual work you did.
I haven't yet found an Android app that includes a ticking sound (which seems like a useful ambient context), and the only MP3 I could find online was behind a paywall, so I just edited this together in half a pomodoro. This MP3 uses ticking, ratcheting and chime sounds from The Free Sound Project - they were all released under a CC Sampling Plus 1.0 licence, and so is this.