Volvo S80 2007-2010 4.4L. it's better send us your OE + Picture even another fuel injector is okay,we can Find &Design for you. Volvo XC90 2005-2011 4.4L.
Filters and O-rings are good quality. Removal tool destroys original.
Lacking are the retainer rings that hold the upper O-ring in place, thus preventing the FI from slipping out of the fuel rail while it is jockyed as the Fuel Injectors are inserted into each cylinder head opening. However, these are not essential, given sufficent care.
A kit should include retaining rings as the originals become brittle and break due to engine heat/cooling cycles.
Soak fuel injectors, sans O-rings, in curbuetor cleaner to remove varnish, then rebuild. If you plan to acutate the mechanism to run carb cleaner through FI, do not apply more than 6-8 volts to FI not to risk damage.