The 179733 filter seal is placed in the bottom of the main gun body where the handle threads into the gun. This was a commonly used ring on the original Graco Contractor spray guns, Contractor II and the Graco In-Line Valve airless sprayer gun.
Part #: 288749
Part #: 243004
Part #: 120733
Part #: 15B958
Part #: 288817
Part #: 221413