I use a Blockmaster Safestick. They are used by the British Government and the NHS to secure data. It has encryption at a hardware level, when you plug it into a computer you get prompted for your password which you set up at first use. Without the password it’s just about impossible to access anything stored on it, with AES256 encryption.
You can store copies of your offline/paper wallets on it along with any PGP keys or anything else you need to protect. It’s one of the best things I’ve bought, highly recommended.