iPhone 4 16gb t mobile mint condition boxed with all acc sale or swap ?

iPhone 4 16gb on t mobile not sure if takes other sim phone is in fantastic condition comes boxed with all its bits, comes with four back covers all new in packs mixed colours and a black leather case , looking to sell or swap for iPad good tablet or laptop, phone is pick up from great dunmow Essex between stanstead and Braintree not to far from Chelmsford thanks for looking