5204 Nachi Double Row Angular Ball Bearing, Made in Japan, inner diameter is 20mm, outer diameter is 47mm and width is 20.6mm.
The construction of this type ball bearing is similar to the adjacent, BACK-TO-BACK mounting of two Single-row Angular Contact ball bearings. Because fewer balls can be inserted per row compared to Single-row Angular Contact ball bearings, a Double-row Angular Contact ball bearing will have less load capacity than an equivalent size/series BACK-TO-BACK set of two Single-row Angular Contact ball bearings. This bearing type can sustain radial, moment and bi-directional axial loads.
Saw bearings 
