There are many offline wallets that you can use, but always be careful when choosing the left one because there are still many offline wallets that is not trustable because of being prone of some attacks by the hackers, or those wallets that are not really secured. Always do a well research when trying some offline wallet or even online wallet because research and having knowledge is the best things you will have to secure your money.

If you want a list of good and trusted offline wallet you may visit this thread: https://bitcointalk.org/index.php?topic=5246017.msg54366883#msg54366883