Estimated 10-Year battery life with included CR2032 model battery ensures long-life before needing servicing 100M / 10ATM Water resistance provides safety during water activities Casio "Illuminator" with LED Backlight aids visibility in darker environments Additional features include Day-Date-Month Display, 5-Alarms, and a 1/100-Second Stopwatch with measuring capacity of 23:59'59.99"