Iphone 4s on ios6 in excellent condition a few months old just like new +

This is an excellent iphone4s 16G with the latest IOS 6 software on it. All boxed with charger and earpiece. its on vodafone but i am not sure if its locked or unlocked. A reasonable offer is acceptable. Only selling due to the latest iphone5 that i want to get asap. GOOD thing about it is that the battery last longer than other iphone4s but i dont why this one lasts longer than other iphone4s as people do complain about the battery but this one is excellent.