on the sides of 90-92 stock catalytic converters and allow you to remove the entire AIV system while retaining the OEM main cats.
pic shamelessly lifted from YugoBernie
One pair of plugs pictured in new unused condition for $16 shipped. Never got around to using these before installing my TP. Offered on a satisfaction guaranteed basis if returned within ten days of receipt.
Follow Ups
AIV delete plugs. These cap the openings - 240Z FeO221:13:17 06/20/09