For cold storage, a stainless steel wallet is pretty safe.

https://www.indiegogo.com/projects/cryptosteel-the-ultimate-cold-storage-wallet#/

http://themerkle.com/wp-content/uploads/2015/03/crypto-steel-1.jpg

http://res.cloudinary.com/indiegogo-media-prod-cld/image/upload/c_limit,w_620/v1431881959/i0d3x8onbr7ozrz5wjaz.jpg