A permitted device, used in some English coal mines, that resembles Cardox in that a steel cylinder with a thin shearing disk is used. However, the charge is not liquid carbon dioxide but rather a powder composed chiefly of ammonium chloride and sodium nitrate. It is proportioned to give water, nitrogen, and salt as the products of combustion. On being ignited, this powder is gasified and shears the steel disk, with the gas escaping into the hole.