The device shall be of the slotted-jaw type. The opening at the centre of the locking pin shall be 60 mm + 0,5/- 1,5 mm and the depth of the jaw measured from the centre of the pin shall be 62 mm ± 0,5 mm.
The coupling pin must have a diameter of 30 + 1,5 mm and be fitted with a device preventing it from leaving its seating during use. The securing device must be non-detachable.
The tolerance of + 1,5 mm referred to above should not be regarded as a manufacturing tolerance but as a permissible variation in nominal dimensions for pins of different designs.