This is the screw Cap (NC Miata 2006 - 2013) that keeps getting pulling into dark mysterious black holes when driving. These tend to fall of due to the Miata's body rigidity. Just print a couple out when you loose them. Version 1.0 is modeled after OEM and Version 1.1 has a cutout for a screwdriver to fit in ,thus allowing it to be removed.
Suggested to print with either PLA or ABS at 100% fill. Its a quick 20 min print. Enjoy and share.
Printed and tested for fit with PLA. Pretty easy print. Print in Black to match or any other color to be cool ;)