Dometic Grand Aero 3
My advice: try before you buy, if at all possible. Most after-market mirrors are not worth having. They are too flimsy; too wobbly; bad optics; etc. You won't know until you see them in action. No mirrors are perfect, so you'll be checking their flaws to see what you can consider acceptable for the price you're paying.
I chose those Grand Aero's after trying a number of different types. These are quite pricey, but right now they are on sale for a good price at Dyersonline.
McKesh mirrors are considered by many to be the gold standard in towing mirrors. I had a set of them once, and they were marvelous. Again - pricey. But I chose to sell them because I didn't like the very large blind spot they created for me. They are big! But they were very stable and had great optics. Fortunately, because of their reputation, I was able to sell them for a pretty good price, even though they were several years old when I sold them.