iPhone Duo Only Works With the $79 USB-C Apple Pencil, Not the Apple Pencil Pro

The iPhone Duo will work with the Apple Pencil , but support is limited. Apple says that you need the ‌Apple Pencil‌ with USB-C for the iPhone Duo, so if you have the ‌Apple Pencil‌ Pro, you may be out of luck. It's likely the iPhone Duo doesn't support the ‌Apple Pencil‌ Pro because there's no magnetic surface for charging the pencil.