Does just what I need, and much more

I just needed something that would beep every 20 minutes so I can keep my iCloud session alive while Im reading. I suppose I could use it for banking sites, too. This app is much more capable than that--several sets of triple routines--but it is not hard to figure out how to use just a single routine (just set the others to 0:00 and to play no sound). It plays music too.

David Stafford about Interval Timer - Tabata Timer, v3.0.3