Best free offline folder synchronization apps for android


Hi all, I'm di0rdna. I'm new to this forum. :)

I’ve been trying a few sync apps to keep my files in android devices sync with my external hard disk. Unfortunately, most of them is online solution such as cloud, not offline.

I’m looking a solution whereby I don’t have to be online to sync my files & folder from android devices to my external hard disk.

If you used to use FreeFileSync, you’ll find it very easy to synchronize files or folders in two or more different locations.
But this is for Microsoft Windows, and I’m looking for similar solutions in android.

Your assistance in this matter would be highly appreciated. Thanks.