torukujulise õhukeseseinalise kerega, mõlemast otsast kuuekandilise keeramisosaga mutrivõti (vrd harkvõti; silmusvõti), spanner composed of a cylindrical piece of steel shaped at one end or both ends to a hexagon in order to fit over appropriate nut; the spanner is turned by a steel rod (tommy bar) inserted through a diametrically drilled hole at the opposite end to the hexagon in use (compare: ope-end spanner; ring spanner)