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

Apple in 2015 unveiled the original Apple Pencil, its first stylus designed to work with the first-generation iPad Pro. Former Apple CEO Steve Jobs was famously against styluses, but the Apple Pencil has proven to be a useful tool for note taking, sketching, and more with the tablet form factor. The Apple Pencil has stuck around since 2015, and as of today, all of Apple's iPads work with one of the four Apple Pencil models that Apple has introduced.