How do i identify an authentic tiffany necklace and braclet?

I have a Tiffany Co. heart tag charm necklace and matching bracelet, how can i tell if these are authentic or knock-off items?|||Yea, go to Tiffany %26amp; Co. and ask them.|||Well it should say Please Return to Tiffany %26amp; Co. New York 925 on the front (if it's the bracelet i'm thinking of). Also it should have the copyright c on the back with Tiffany %26amp; Co 925|||Go to Tiffany and ask them.|||It better say Ynaffit when you look in the mirror, then it is 100% real|||it should say tiffany%26amp;co