This is a A-SBK1 Shield Bearing Kit PN: SBK1Main Description As Following : A-SBK1 Shield Bearing Kit P.N: SBK1 Series: W 2100 Found in Section & Models : Driveline > Driveline Components, Bondioli & Pavesi 100 Series: Size 1, Bondioli & Pavesi 100 Series: Size 2, Walterscheid W Series: 2100 Associated Items : New Also This is An Aftermarket Product And : Series: W 2100