Anyone know what these grounds are for?

[OR VietVet]

The heads of those bolts look like you will try at least 4 sizes, metric and SAE, before you get enough rust to break off to get to solid steel.

https://www.amazon.com/RIDGE-WASHER-Pressure-Undercarriage-Extension/dp/B08N47F8DK/ref=sr_1_1_sspa?crid=2ZONMEM0RIQ2B&keywords=under+car+sprayer&qid=1694015124&sprefix=under+car+sprayer%2Caps%2C193&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

 

[RAMurphy]

The heads of those bolts look like you will try at least 4 sizes, metric and SAE, before you get enough rust to break off to get to solid steel.

https://www.amazon.com/RIDGE-WASHER-Pressure-Undercarriage-Extension/dp/B08N47F8DK/ref=sr_1_1_sspa?crid=2ZONMEM0RIQ2B&keywords=under+car+sprayer&qid=1694015124&sprefix=under+car+sprayer%2Caps%2C193&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Neat concept.