105 mm x 190 mm x 36 mm NKE 1221 self aligning ball bearings

LET BEARING Driveshaft USA CORP. OUR 105 mm x 190 mm x 36 mm NKE 1221 self aligning ball bearings EXPERTS GET YOU 6.05 Dynamic Load Rating (kN): 17mm d THE 105 mm x 190 mm x 36 mm PARTS YOU NEED.

What is 1221 bearing interchange？