| Part Number | 638ZZ |
| System of Measurement | Metric |
| Bearing Type | Ball |
| For Load Direction | Radial |
| Construction | Single Row |
| Seal Type | Shielded |
| Bore Dia | 8 mm |
| Bore Dia Tolerance | -0.008 to 0 mm |
| Outer Dia | 28 mm |
| Outer Dia Tolerance | -0.008 to 0 mm |
| Width | 9 mm |
| Width Tolerance | -0.12 to 0 mm |
| Ring Material | 52100 Chrome Steel (Gcr15) |
| Ball Material | 52100 Chrome Steel (Gcr15) |
| Cage Material | 300 Series Stainless Steel |
| Shield Material | 300 Series Stainless Steel |
| Dynamic Radial Load | 3879 N |
| Static Radial Load | 1586 N |
| Max Speed (X1000 rpm) | 28 |
| Lubrication | Pre-filled / Required |
| Shaft Mount Type | Press Fit |
| Temperature Range | -30 ℃ to 110 ℃ |
| ABEC Rating | ABEC-1 (higher grade available) |
| Radial Clearance Trade No. | MC3 (other clearance available) |
| Radial Clearance | 0.002 to 0.013 mm |
| RoHS | Compliant |
| REACH | Compliant |
| Ball Dia | 4.762 mm |
| Ball Qty | 7 |
| Weight | 30.3 g |
