põllu- või metsamajanduses kasutatav mehhanism, mille peamine otstarve on täiendada või muuta traktori funktsioone ja mis on konstrueeritud traktori haakes vedamiseks, any instrument used in agriculture or forestry which is designed to be towed by a tractor and changes or adds to its functions; it may include a load platform designed and constructed to receive any tools and appliances needed for those purposes, and to store temporarily any materials produced or needed during work; any vehicle intended to be towed by a tractor and permanently incorporating an implement or designed to process materials shall be considered interchangeable towed machinery if the ratio of the technically permissible gross mass to the unladen mass of that vehicle is less than 3,0