Italian Grades
| Grade | Diameter (mm) | Sphericity (µm) | Diameter Variation (µm) | Shipment Diameter (µm) | Maximum Roughness (µm) | ISO* Grade | DIN* Grade | AFBMA* Grade |
| AAAA | 0-3 inc | 0.15 | 0.3 | ± 1.5 | 0.010 | 5 | - | 5 |
| over 3-6 inc | 0.2 | 0.4 | ± 2 | 0.013 | 10 | - | 10 | |
| over 6-10 inc | 0.2 | 0.4 | ± 3 | 0.015 | 10 | I | 10 | |
| over 10-20 inc | 0.4 | 0.8 | ± 4 | 0.020 | 16 | - | 16 | |
| over 20-30 inc | 0.6 | 1.2 | ± 5 | 0.023 | - | II | 24 | |
| over 30-50 inc | 0.9 | 1.8 | ± 6 | 0.028 | - | - | 24 | |
| AAA | 0-3 inc | 0.2 | 0.5 | ± 2 | 0.012 | 10 | I | 10 |
| over 3-6 inc | 0.3 | 0.6 | ± 3 | 0.015 | 16 | I | 16 | |
| over 6-10 inc | 0.4 | 0.8 | ± 4 | 0.018 | 16 | II | 16 | |
| over 10-20 inc | 0.5 | 1 | ± 5 | 0.022 | 20 | II | 16 | |
| over 20-30 inc | 0.8 | 1.5 | ± 6 | 0.025 | 28 | - | 24 | |
| over 30-50 inc | 1 | 2 | ± 8 | 0.030 | 40 | - | 48 | |
| AA | 0-3 inc | 0.4 | 0.8 | ± 4 | 0.015 | 16 | II | 16 |
| over 3-6 inc | 0.5 | 1 | ± 5 | 0.018 | 28 | II | 24 | |
| over 6-10 inc | 0.6 | 1.2 | ± 6 | 0.022 | 28 | III | 24 | |
| over 10-20 inc | 0.8 | 1.5 | ± 7.5 | 0.025 | 28 | III | 24 | |
| over 20-30 inc | 1 | 2 | ± 10 | 0.030 | 40 | III | 48 | |
| over 30-50 inc | 1.5 | 3 | ± 12 | 0.035 |
- | III | 48 | |
| A | 0-3 inc | 0.8 | 1.2 | ± 6 | 0.020 | 28 | III | 24 |
| over 3-6 inc | 1 | 1.5 | ± 7.5 | 0.023 | 40 | III | 48 | |
| over 6-10 inc | 1.2 | 2 | ± 8 | 0.026 | 40 | - | 48 | |
| over 10-20 inc | 1.5 | 2.5 | ± 10 | 0.030 | 40 | IV | 48 | |
| over 20-30 inc | 2 | 3 | ± 15 | 0.035 | 100 | IV | 100 | |
| over 30-50 inc | 2 | 4 | ± 20 | 0.040 | 100 | IV | 100 | |
| B | 0-3 inc | 1.2 | 2.5 | ± 7.5 | 0.040 | 40 | III | 48 |
| over 3-6 inc | 1.5 | 3 | ± 9 | 0.050 | 100 | III | 100 | |
| over 6-10 inc | 2 | 4 | ± 12 | 0.060 | 100 | IV | 100 | |
| over 10-20 inc | 2.5 | 5 | ± 15 | 0.080 | 100 | IV | 100 | |
| over 20-30 inc | 3 | 6 | ± 24 | 0.100 | 200 | IV | 200 | |
| over 30-50 inc | 4 | 8 | ± 32 | 0.120 |
200 | IV | 200 | |
| C | 0-3 inc | 3 | 6 | ± 12 | - | 100 | IV | 100 |
| over 3-6 inc | 4 | 8 | ± 16 | - | - | IV | 100 | |
| over 6-10 inc | 5 | 10 | ± 20 | - | 200 | IV | 200 | |
| over 10-20 inc | 8 | 15 | ± 30 | - | 200 | V | 200 | |
| over 20-30 inc | 10 | 20 | ± 40 | - | - | V | 300 | |
| over 30-50 inc | 12 | 25 | ± 50 | - | - | V | 300 | |
| D | 0-3 inc | 30 | 30 | ± 50 | - | - | V | 500 |
| over 3-6 inc | 30 | 30 | ± 50 | - | - | V | 1000 | |
| over 6-10 inc | 40 | 40 | ± 75 | - | - | V | 1000 | |
| over 10-20 inc | 50 | 50 | ± 125 | - | - | V | 1000 | |
| over 20-30 inc | 50 | 50 | ± 125 | - | - | V | 1000 |
*These comparisons should be taken as a general guide. Always consult the relevant specification for total accuracy.