This part of ISO 11001 specifies the essential dimensions for the attachment of three-point hitch implements to agricultural wheeled tractors equipped with a three-point free link hitch according to ISO 730-1 or ISO 8759-2, and an A-frame hitch coupler. NOTE 1 In general the dimensions associated with the tractor and the implement for use with hitch couplers are the same as those for the three-point linkage specified in ISO 730-1 or ISO 8759-2, and those for the clearance zone specified in ISO 23321). The three-point hitch coupler systems constitute a special method of implement mounting. The hitch couplers are an additional component located between the three-point linkage and the implement, making it possible to hitch and unhitch from the operator's seat. Due to the special construction and function of hitch couplers, it may be necessary to vary the length of the links indicated in the referenced standards. This part of ISO 11001 applies to category 2 of agricultural wheeled tractors as defined in ISO 730-1.