How to use the countdown timer?

Please first enable the countdown timer feature and set the usual time in the H Band app (Mine > Y39 > Countdown Timer). Once you long-press the function button on the Countdown timer interface of your fitness tracker, the timer will start, and an hourglass will be displayed on the screen. The remaining time of the countdown timer will be shown in the H Band app, and the fitness tracker will vibrate to remind you when the countdown timer ends.