hi
I wear a Casio digital watch, I call it flying watch, It has a count down timer function, and most important of all, you have a choice to hear the beep or feel the vibration in your hand waist when time is up. You know, I don't have eyes on the watch during flying nor somtimes it is too noisy that I can't hear the beep so vibration alert is a perfect match to me. I've been wearing it for years.

Hope you can have one too