The main differences are in storage capacity and wireless capabilities. The Nano X is physically larger, and its significantly greater storage capacity allows it to store over 30 applications at a time. In contrast the Nano S can only hold a maximum of three at one time, meaning that if you are dealing with four or more cryptocurrencies, you will need to uninstall and reinstall different apps as use create transactions with different coins. Furthermore, whereas the Nano S needs to connect to your phone or computer with a cable, the X can interact with your mobile device wirelessly. Finally, the Nano S cannot be used with iPhone devices, whereas the X can. The Nano X’s additional features do come with a higher price point. Whereas the Nano S costs $120, the Nano X is $200. Both are equally secure, which is what really matters in the end!