In my opinion, 'device for' is a correct form. You can say, for instance, device for IPhone etc.
I think in this case experience is more important than rules, as there are lots of exceptions to these rules.
For me the most difficult thing in English is phrasal verbs. There are really lots of different combinations 'verb+particle' (e.g. carry on, carry out etc.), and sometimes only dictionary of phrasal verbs can help.