Casio General Men's Watches Digital TRT-100H-2AVHDF - WW Mud resistant controls, 100 Meter water resistant Double Illuminator backlight, Double electro- luminescent backlight, Dual time 1/100 second stop watch - Measuring capacity: 23:59'59.99, Measuring mode: net time, Daily alarm Auto-calendar (set at 28 days for february), 12/24 hour formats,Accuracy: +_ 30 seconds per month, Battery: Approximately 3 years on CR2016