New dust shield.  This is RH (passenger's) side (starter side).  This plastic shield attaches to the oil pan to keep debris from entering the transmission.  This is for factory GTO oil pans only, being used with a T56 transmission. Cover only (no bolt).  Fits the following:

04-06 LS1/LS2 GTO w/ T56 transmission

NOTE : These dust shields are very application specific to the oil pan and bell housing, they must match for them to work properly!