That is a simple battery powered tracking device that will mount on nearly any tripod, but a sturdy tripod is recommended. you don’t necessarily need it for the iPhone because the iPhone only will take a 30 second exposure. It will come in handy if you plan on taking multiple 30 second exposures so you can track the sky and stack all of the images to come out with a much cleaner photo. Here is a link to Amazon for that device and you can also go to the Skywatcher website and read up on it further.
Sky-Watcher Star Adventurer 2i Pro Pack – Motorized DSLR Night Sky Tracker Equatorial Mount for Portable Nightscapes, Time-Lapse and Panoramas – Wi-Fi App Camera Control – Long Exposure (S20512)
https://a.co/d/iK0LJRl