randomised countdown timer

[dangerous dave]

dose any one know where i can get a randomised countdown timer wich sets of an alarm i want to pratice my bug out stratagy but want to be able to do it from no notice just a alarm then to time reaction times too
i know it may sound stupid to some but in an emergency time is everything

thanks
DD

[preppingsu]

If you have a smartphone try this

https://play.google.com/store/apps/deta ... ller&hl=en