Porsche 924 2.0 fuel injector holder insert 063 133 555 ((CB31d))
This is the insert that sits inside your cylinder head that holds the fuel injector for 2.0 NA cars. Porsche part number is 063 133 555. It is removed from head with a 17mm hex key. Usually hard to remove as they have been in there since the 80's. They can crack and cause air leaks which causes running issues.
4 required per car.
Item number 28 in the image.