In times past, it was best to give the adapter with the device since everyone had their own power plug and you couldn't reuse one with another. Like going from a Nokia to a Motorola phone, for example, needed a different supply. However, this era is now filled with standard USB power bricks for every gadget out there. You have any device made in the last 15 years and it has USB it works with the cable they include with this watch. You can plug into computers for charging, cars, airplanes, etc. And if worst comes to worst, you don't have a power brick, well you can pay like $5 for one that doesn't have to be Apple, or if you want Apple get the Apple one and keep it for life! It's yours now! These things last forever! Seriously I haven't had a USB brick go bad, so long as I can replace the cable (cables fray and need to be replaced but the bricks haven't gone bad yet).