New ATP tailshaft extension housing seal.  This is the output shaft seal, which seals the driveshaft.  Fits the following:

70-81 Camaro w/ TH350 transmission
70-81 Firebird/Trans Am w/ TH350 transmission
83-92 Camaro w/ 700R4 transmission
83-92 Firebird/Trans Am w/ 700R4 transmission