Casio General x Digital ft. Retro Vintage Men Women Casual Formal Tonneau 50m Water Resistant Watch B640WB-1A B640WB B640 B-640 B-640WB Experience precise timekeeping with this stylish watch, featuring a 3-year battery life, LED backlight, and 50m water resistance. Stay on top of your schedule with a 1/100-second stopwatch, countdown timer, and multi-function alarm. Perfect for everyday wear, this watch combines retro vintage style with modern function Battery Life / Accuracy Approximately 3 years (+/-30 seconds per month) Crystal Resin glass Light LED backlight (afterglow) Case & Band Material Resin (chrome plated) case with metal band (slide clasp) Water Resistance 50m / 5 bar Case Size Thickness: 9.4 mm Diameter: 35.0 mm Length: 38.9 mm Other Specifications Casio General x Digital ft. Retro Vintage 1/100-second stopwatch Countdown timer Hourly time signal Multi-function alarm Flash alert (flashes with buzzer that sounds) Full auto-calendar (to year 2039) 12/24-hour format Regular timekeeping (digital display)