Features: 1. Shutdown function: Power can be turned off while retaining time and date settings. 2. Key mute function: Enables silent operation in quiet environments. 3. Time and calendar function: Displays year, month, day, hour, minute, second, and weekday; supports 12-hour and 24-hour formats. 4. Stopwatch function: Triple-line display with split-time memory storage; accuracy up to 1/100 second; maximum timing duration: 9 hours, 59 minutes, 59 seconds. 5. Performance metrics: Displays fastest, slowest, and average lap times. Memory data can be scrolled forward and backward. 6. Countdown function: Adjustable countdown timer with maximum duration of 9 hours, 59 minutes, 59 seconds. 7. Daily alarm function: Quick on/off control for alarm activation. 8. Metronome function: Adjustable tempo from 5 to 320 beats per minute (in increments of 5). Specifications: Model: YS810 / YS830 / YS860 / YS8100 Color: White / Black Display: Triple-line LCD; supports 10 / 30 / 60 / 100 lap tracking Material: ABS plastic housing Battery: Built-in CR2032 coin cell battery 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