How do you keep grass away from your Pop-Up Sprinkler heads?

I need to know of small plastics stakes (12â long with resistance to protect mowers) I can drive in the ground to hold Pop Up HeadâÂÂs Donuts in place (as an effort but too light).

1. We can water two days a week with restricted hrs and conditions as no runoff water into the street.
2. With grass grown over heads by the curb and grass showing a need this becomes a problem.
3. I suggested the tool that trims the heads and the son did plus added the donuts to restrict grass.
4. Their donut is not practical since itâÂÂs not anchored, moves and the yardmanâÂÂs mower has gotten some.
5. I offered to state the plastic donuts if I can find small 12â long plastic that I can drive into the ground.
6. Today I saw the donuts online with extensions as good as stakes but would like stakes for her present donuts.
7. My solution has been thick PVC pipe sleeves to resist my hard blade when trimming with fewer gear fed heads.

Please share other ideas as adding a PVC sleeve with a flange to hold the donut vs a stake.