| 1 | Earpiece dimensions and tolerances. | |
| 2 | Establish tolerances at each critical control point. | |
| 3 | A commercial straightness tolerance of 5mm maximum deviation over 1 metre will apply. | |
| 4 | Assembly tools for screws and nuts. Wrench and socket openings. Tolerances for general use. | |
| 5 | Measurement will be conducted with instruments suitable for the applied tolerances. |