An improved key for a dry wall block system is provided with a plurality of longitudinal flanges and a common web. The carbonaceous ash and ancillary fuels are fed into a thermal reactor along with oxides provided in the ash or in additives including limestone or glass. A push rod control is provided for accurately controllably positioning the head within the finishing apparatus. The first sensor and the second sensor are respectively packaged into the separate first and second cavities within the molded sensor head of the sensor assembly to provide a sensor apparatus that provides for multiple and varying sensor capabilities. The container may be a cartridge for use in the machine, or a container for packaging the ink stick.