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, ISO 730-3 or ISO 8759-2, and a U-frame hitch coupler. 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. Applies to categories 2, 3 and 4 of agricultural wheeled tractors as defined in ISO 730-1 and ISO 730-3.