Part Number | 
                            
                              d - Bore | 
                            
                              D - Outer Diameter | 
                            
                              B - Width | 
                           
                            
                              Bearing Type |  
                          
|---|---|---|---|---|
| D/W R4 | 6.35 mm | 15.875 mm | 4.978 mm | Deep groove ball bearing | 
| D/W R188-2Z | 6.35 mm | 12.7 mm | 4.762 mm | Deep groove ball bearing | 
| D/W R4-2Z | 6.35 mm | 15.875 mm | 4.978 mm | Deep groove ball bearing | 
| D/W R188 R | 6.35 mm | 12.7 mm | 3.175 mm | Deep groove ball bearing | 
| D/W R4 R-2Z | 6.35 mm | 15.875 mm | 4.978 mm | Deep groove ball bearing | 
| D/W RW4 | 6.35 mm | 15.875 mm | 5.77 mm | Deep groove ball bearing | 
| D/W R168-2ZS | 6.35 mm | 9.525 mm | 3.175 mm | Deep groove ball bearing | 
| D/W R168 | 6.35 mm | 9.525 mm | 3.175 mm | Deep groove ball bearing | 
| D/W RW168-2ZS | 6.35 mm | 9.525 mm | 3.967 mm | Deep groove ball bearing | 
| D/W R188 | 6.35 mm | 12.7 mm | 3.175 mm | Deep groove ball bearing | 
| D/W R4-2RZ | 6.35 mm | 15.875 mm | 4.978 mm | Deep groove ball bearing | 
| D/W R188 R-2Z | 6.35 mm | 12.7 mm | 4.762 mm | Deep groove ball bearing | 
| D/W RW168 R | 6.35 mm | 9.525 mm | 3.967 mm | Deep groove ball bearing | 
| D/W R4A-2RZ | 6.35 mm | 19.05 mm | 7.142 mm | Deep groove ball bearing | 
| D/W R4 R-2RZ | 6.35 mm | 15.875 mm | 4.978 mm | Deep groove ball bearing | 
| WBB1-8707 R-2Z | 7 mm | 13 mm | 4 mm | Deep groove ball bearing | 
| W 619/7 | 7 mm | 17 mm | 5 mm | Deep groove ball bearing | 
| W 637-2RZ | 7 mm | 26 mm | 9 mm | Deep groove ball bearing | 
| W 627-2RS1 | 7 mm | 22 mm | 7 mm | Deep groove ball bearing | 
| 618/7 | 7 mm | 14 mm | 3.5 mm | Deep groove ball bearing |