One of the safest i can think of is the Ledger Nano S is the most popular hardware wallet available, and it supports Litecoin.

If you have a lot of Litecoins, this is the most secure and robust way to store them. It not only allows you to control your private keys, but they are also controlled in an offline environment. It comes with an inbuilt OLED screen, a backup seed key, and a pin code feature. This is how you can restore your funds in case something goes wrong with your hardware device