"Does this watch set itself according to the atomic clock?"に関する回答No, you need to set this watch yourself using whatever time you feel is most accurate. Set the time by pulling the crown out and adjusting the hands until it shows the correct time.
"What kind of battery does this use?"に関する回答This watch should use a Silver Oxide battery by such brands as Energizer, Maxell or Sony and is rated to have a 2-3 year lifespan.
"Can I wear this watch while swimming or showering?"に関する回答Yes, this watch is ok to be worn in the shower and swimming up to 50 meters. It should not rust or break!