This is the OEM rubber o ring gasket that is used on the 2000-2004 Toyota 3RZ throttle bodies for the IAC valve. What is an IAC it is an idle air compensator valve directly associated with the idle control on the 3RZ. When changing to a big bore or removing for the cleaning of the IAC valve this gasket must be in good shape or you can experience a vacuum leak it this area. A vacuum leak will mean that you will have problems getting the engine to idle correctly.
OEM Toyota Part #: 22215-7A6800
Contact our Tech Support Line for further information at 928-855-6341.