The Casio F91WB-8A is a slim, lightweight digital watch with a black resin case, LCD screen, and black bio-based resin strap, combining classic style with environmentally conscious materials. Measuring 38.2 × 35.2 × 8.5mm and weighing 21g, it’s comfortable for everyday wear and fits band sizes from 145 to 200mm. Powered by a CR2016 battery with approx. 7-year life, it offers 1/100-second stopwatch, daily alarm, hourly time signal, and a green LED light for easy readability. The auto-calendar (February set to 28 days), 12/24-hour format, and water resistance ensure reliable performance. Accurate to ±30 seconds per month, it displays hour, minute, second, pm, date, and day, making it a practical and stylish choice for daily wear. - Case Size: 38.2 × 35.2 × 8.5mm - Weight: 21g - Materials: Resin case and bezel, bio-based resin band, resin glass - Compatible Band Size: 145–200mm - Water Resistance: Water resistant - Power: Approx. 7-year battery life (CR2016) - Functions: 1/100-second stopwatch, daily alarm, hourly time signal - Light: Green LED - Calendar: Auto-calendar (February set to 28 days) - Other Features: 12/24-hour format - Accuracy: ±30 seconds per month - Display: Hour, minute, second, pm, date, day