Craft: prestressed wire winding and welding on the basis of merits from German craft. Material: high pressure seamless alloy pipe (rod body); high wear-resistant T-shape strip steel (spiral); medium carbon alloy steel which has been thermal refined in vacuum (connector). Connection type between rods: spring pin with U-shape or semi-ring retaining pin, which guarantees the max torque of the rod. Matching: portable or hand-held drilling machine Feature: light, quick connection, quick slagging, high efficiency. Application: water & gas exploration of coal seam or similar stratum. Rods with drainage hole and without are available.