Just get Apple 20W brick. I got the expensive ass 35w with two ports to charge my Watch as well. Why i didnt get 3rd party much cheaper charger? Cuz I already spent so much on both iPhone and Watch so i wont cheap out on a charger. Despite popular consensus that any charger will do its job properly i dont believe thats true, i watched comparisions made by electricians and these 3rd party chargers differ very much from each other so ill trust Apple specs