eriballast, mis on ette nähtud võrdlusvahendina liiteseadiste katsetamisel, võrdluslampide valikul ja regulaarselt toodetavate elektrilampide katsetamisel standarditud oludes, special ballast designed for the purpose of providing comparison standards for use in testing ballasts, for the selection of reference lamps and for testing electric lamps from regular production under standardized conditions