Features: 1. Shutdown function: Power can be turned off without resetting the clock. 2. Key mute function: Enables silent operation in quiet environments. 3. Time and calendar function: Displays year, month, day, hour, minute, second, and weekday; 12-hour or 24-hour format selectable. 4. Stopwatch function: Triple-line display with split memory storage; accuracy up to 1/100 second; maximum timing duration: 9 hours, 59 minutes, 59 seconds. 5. View fastest, slowest, and average lap times. Memory data can be scrolled up or down for easy review. All functions are intuitive and user-friendly. 6. Countdown function: Adjustable countdown timer with maximum duration of 9 hours, 59 minutes, 59 seconds. 7. Daily alarm function: Quick enable/disable control. 8. Metronome function: Adjustable tempo from 5 to 320 BPM (in increments of 5); includes timing functionality. Specifications: Model: YS810 / YS830 / YS860 / YS8100 Color: White / Black Display: Triple-line LCD showing up to 10 / 30 / 60 / 100 laps Material: ABS plastic housing Battery: Built-in CR2032 button cell Display size: 35 x 23.5 mm (1.38 x 0.93 in) Product size: 75 x 62 x 21 mm (2.95 x 2.44 x 0.83 in) Weight: 70 g