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