| MPJ | Number of tooth of pinion wheel | Gear ratio |
| Gearboxes with ball bearing (BB) | ||
| 8120 | 15 | 2,8:1 |
| 8121 | 18 | 2,33:1 |
| 8122 | 24 | 1,75:1 |
| Pinion wheels, diameter of hole 3,2 mm | ||
| 8123 | 11 | 2,8:1 |
| 8124 | 13 | 2,33:1 |
| 8125 | 15 | 1,75:1 |

| MPJ | Number of tooth of pinion wheel | Gear ratio |
| Gearboxes with ball bearing (BB) | ||
| 8120 | 15 | 2,8:1 |
| 8121 | 18 | 2,33:1 |
| 8122 | 24 | 1,75:1 |
| Pinion wheels, diameter of hole 3,2 mm | ||
| 8123 | 11 | 2,8:1 |
| 8124 | 13 | 2,33:1 |
| 8125 | 15 | 1,75:1 |
