If you have a smart phone you can down load a timer app that works.
Problem for me would be I don't dry fire in my office where my comp is??Really don't want a regular timer and not interested in splits between shots and keeping tabs on shots .
The ones I had on my computer for 4-5 yrs. served my needs well . All I want is a random beep to draw and a second beep that I can set the par time on .