This is an adapter for cheap Harbor Freight tent stakes to mount 1/2" PVC to the top. Adapter friction fits to the PVC as well as the tent stake. The plastic tab on the tent stake goes through the square hole on the back of the adapter, and can be zip tied to secure if desired. PVC can then be cut/drilled/spaced to suit and mounted on the top of the adapter after the stake has been pounded into the ground.

https://www.harborfreight.com/10-inch-steel-tent-stakes-set-of-six-96534.html