Mig Flash is a 3rd party back-up, preservation and development device for the Nintendo Switch© not endorsed nor license by Nintendo© of Japan. Before ordering or using Mig Flash, you must carefully document yourself about the legality of creating backups of your own game cartridges in your country/jurisdiction or modifying your console, even running your own software on it (homebrew).
Backing up your own legally owned games is surprisingly not permitted in every country and can constitute a serious offense in some. Neither is console customization, running homebrew etc.
Game card preservation is one of the most important request from true gamers, particularly as a console/device gets older. Mig Flash is the best answer to provide safe game card preservation. However again there, you must document yourself about the legality in the country you reside, as despite the global consensus on game card preservation, it might be illegal in some country/jurisdiction.