I have found this info at the apple watch sport website: "two bracelets"
Scroll down to see it: http://store.apple.com/de/buy-watch/apple-watch-sport?product=MJ2T2FD/A&step=detail
Scroll down to see it: http://store.apple.com/de/buy-watch/apple-watch-sport?product=MJ2T2FD/A&step=detail