All are authentic except one of them was a chinese deal where it had a different cord type.  All have lots and lots of use.  All are functioning, although they do not work as well as they did when they were new.  Expect for the buttons to be less responsive than with new mouse buttons.  This lot of 7 mice would be good for use for parts.  Or refurbishing if you have parts and supplies for doing refurbishing.  Cosmetic yellowing.