EpceeHeavy Duty Steel Fence Post Repair Stakes, Fence Post Anchor Ground Spike, for Repair Tilted/Broken Wood Fence Post (4 Pack/Black）

Q: can these be set in concrete?

That I don’t know. They are heavy steel so I imagine they could be. Steel rods are encased in concrete all the time

Q: Can these be used to install a new wooden fence?

You add them but my fence posts were in concrete initially. The bottom of the posts rotted that was next to the ground/concrete. These steel rods are shaped for that concrete. I think it allows for an inch of concrete once they were screwed to the post it was very strong. The post didn’t wobble at all. I got another set for another post