This part of ISO 6489 specifies the dimensional requirements for hitch-hooks used in the attachment to agricultural towing vehicles of towed, non-balanced trailers and implements equipped with a ring specified in ISO 20019. Its purpose is to ensure the interchangeability of the mechanical connections on agricultural towing vehicles.

This part of ISO 6489-1 is applicable only in those cases where the vertical static load does not exceed 30 kN.