'both of' You can't say 'both two the ' ,there is already a definite article 'the' and 'two' is considered a defining word here, so it is wrong to define the words 2 times. You could say 'both Cd's', but since there is the article 'the' you have to separate 'both' and 'the' by 'of' .

I agree with cherry

we gave both of the CDs back to jack.