FitBit Zip Wireless Activity Tracker in Green Clip-on tracker, tracks steps taken, calories burned and distance travelled, Rain, splash and sweat-proof. Tracks steps, distance and calories burned, Set goals, view progress and earn badges, Share and compete with friends throughout the day. Syncs automatically to your computer or select bluetooth 4.0 smartphones or tablets, Sync stats wirelessly and automatically to your computer and over 150 leading smartphones, Free iphone and android application. Runs off a replaceable watch battery (included) - lasts approx 6 months, Battery type: 3v coin battery. Perfect gift or present for your Dad Auntie Uncle Niece Nephew Brother Sister Boyfriend Husband Wife Teenagers.