34,925 mm x 85,725 mm x 30,162 mm Timken 3872/3820 tapered roller bearings

tapered roller bearings offers Open Type Seals or Shields: a NTN BEARING CORP.OF AMERICA 34,925 mm x 85,725 mm x 30,162 mm Timken 3872/3820 tapered roller bearings selection of Genuine tapered roller bearings at 34,925 mm x 85,725 mm x 30,162 mm Wholesale Prices. We are a 34,925 mm x 85,725 mm x 30,162 mm Timken 3872/3820 tapered roller bearings Certified Parts Retailer

What is 3872/3820 bearing interchange？