We like camping mirrors best
Our present towvee is a 2006 Silverado 2500HD 4X4. It came with smallish mirrors with heat, turn signal, other features. We tried for five years using Camco snap-on extensions and twice drove friends' trucks with camping tow mirrors like picture in post #2 above. So much better, great sight picture and easy to switch from towing to urban driving -- just slide them in or out.
We finally pulled the trigger on this project last November. Found them through Amazon, I think, for $250. Perfect fit, wiring harness was just right, directions are good, mirrors look good and work great. Plug and play -- disconnect the wires from the old ones, unbolt and remove the old ones, bolt in the new ones, plug the new wires in, and your work is complete.
Follow the directions, there is one small change you also need make about the automatic rear-view thingy, it was easy and didn't matter to us.
Bottom line, we love the bigger mirrors, the large convex lower section is great for quick check on blind spots and for backing, and the mirrors are rock-steady. Best of all, we no longer remove and replace our mirrors on towing days -- they are always ready. We just extend or retract them -- easy easy.