Gangdong, also known as Ganglin and Zhaling in Tibetan, and Dharma and Lama in Han, evolved from ancient horn-like musical instruments and is one of the instruments of Tibetan Buddhism.

In Baoding, Xushui, Dingxian, Laishui and other places in Hebei Province, copper steel holes are also used, which are used in the performance of "Southern Music Club", and are locally called Lamahao or "Haizhuzi". It can also be seen from the name that it has a relationship with Tibetan Buddhist music. The shape is short and small, with a total length of 38 cm. The upper section is a conical tube body with a mouthpiece at the upper end, and the lower tube body is curved like a horn, with a dragon head carving on it. When playing, the upper section of the pipe body is inserted into the lower section of the pipe about one-half, so that the length of the pipe is shortened to 30 cm. It is mainly used in the beginning, ending or climax of a piece of music. Generally, the tune is not played. It is only played with the tune of 4th or 5th to jump in or play long notes freely, which can enhance the tune or render the atmosphere of the piece. In the "Nan Lehui" in Nanyi'an Village, Laishui County, Gangdong Kaxi is used.

The Chinese Musical Instrument Museum of the Institute of Music of the China Academy of Arts in Beijing has two copper steel holes with the same shape. The tube body is made of red copper and consists of three sections. The total length is 45 cm, the upper section is 16 cm long, the mouthpiece diameter is 2.6 cm, the mouth depth is 1 cm, the aperture is 0.8 cm, the middle section is 15.5 cm long, the lower section is 13.5 cm long, and the lower pipe mouth (long mouth), in the shape of a rectangle, 4.8 cm long , 4 cm wide, with carved dragon head embossed throughout. Silver ornaments are inlaid on the upper, middle and lower ends of the tube body, and a silver ring is arranged under the dragon's mouth, which is decorated with yellow silk ears or silk. These two Gangdongs have been included in the large-scale picture book "Chinese Musical Instruments Illustrated Guide".