It has a metallic case that can be used repeatedly. The case is a thick-walled cylinder and holds an igniting device and charges in it. An electric cable is used for transmission. Ignition location is determined by magnetic locator. The merits include safe operation, low cost, short period, and convenient running in. However, it has metallic cases and a small ignition powder weight; thus, it has been rarely applied at present.  Each powder (or propellant) charge has a hole of Φ20–25 mm at the center of the charge. The gap between the end faces of aluminum base pipe and charge is sealed with sealing compound. The strength of the aluminum base pipe should bear both the external pressure caused by the hold-down water column and the internal pressure generated by the combustion of ignition powder in the base pipe. The lengths of each charge and aluminum base pipe are respectively 500 mm and 510 mm. Both charges are connected to each other by connecting pipe with a length of 130–150 mm. The total quantity of powder is dependent on formation breakdown pressure, hole-down water column height, number of perforations, and perforation diameter. The ignitor is installed at the top. The auxiliary ignition powder in aluminum base pipe is ignited by the ignitor, so that the base pipe is heated to a temperature higher than 2800°C. At the same time, all the propellant charges are ignited.