The Mongolian four hus are divided into four low-pitched hus, mid-voiced four hus, high-pitched four hus, and Mongolian four hus.

Bass Sihu
Bass Sihu, Mongolian bow and stringed musical instrument. Also known as Big Sihu and Haolaibao Sihu, it is widely popular in pastoral areas and semi-agricultural and semi-pastoral areas in Inner Mongolia Autonomous Region.

The bass sihu in the pastoral area can be assembled and disassembled into several parts in order to carry it on a horse, that is, a barrel, two bars, pegs and bows. The qin barrel was first hollowed out with a whole piece of wood to form a cylindrical shape. The barrel was 30 cm long and 15 cm to 20 cm in diameter. . Later, the qin barrel was made of hardwood into round, hexagonal or octagonal. The piano rod is made of wood, mostly in two pieces, with a total length of 110 cm, and four casing strings, silk strings or copper strings. The bow is made of wood or willow branches, and the two ends are tied with ponytails. The length of the bow is 85 cm. Mainly popular in Zhelimu League, Zhaowuda League and Xing'an League and other places. Mainly used for Mongolian rap Haolaibao and Mongolian singing Uligor accompaniment.

The bass sihu in the semi-agricultural and semi-pastoral areas is mostly made of bamboo or hardwood, and is cylindrical or octagonal, with a cylinder length of 25 cm and a diameter (or diagonal) of 14 cm. The stem is made of hardwood with a length of 108 cm and can be used for solo, instrumental ensembles or to accompany rap and song and dance.

Alto Sihu
The alto four-hu, Mongolian bow and stringed musical instrument. It is popular in the agricultural and semi-agricultural and semi-pastoral areas of Inner Mongolia, Liaoning, Jilin, Heilongjiang and other provinces. The shape is the same as the bass four-hu, slightly smaller. The piano barrel is cylindrical and made of thin brass plates, which is 16 cm long and 10 cm in diameter. The front of the barrel is covered with python skin or cowhide. , with a copper frame inside the mouth. The headstock is made of a single piece of mahogany or sandalwood, with a total length of 90 cm. The headstock is flat-topped, with four shafts on top, four silk or copper strings, and two ponytails tied with thin bamboo as a bow, with a bow length of 68 cm.

Treble Sihu
High-pitched four-hu, Mongolian bow and stringed musical instrument. Also known as Mongolian Xiaosihu. It is restructured on the basis of the folk Xiaosihu. The sound is crisp and can be used for solo, instrumental ensemble. Popular in Inner Mongolia, Liaoning, Jilin, Heilongjiang and other provinces.

The folk Xiaosihu, the qin barrel is bamboo or wooden, cylindrical or octagonal, with four axes, four strings, and gut strings or silk strings, and the tone is rough. In the Chinese Musical Instrument Museum of the Music Research Institute of the China Academy of Arts in Beijing, there is a small Sihu in the collection. The qin barrel is made of wood, double-layered, in the shape of an octagonal barrel, with a barrel length of 13.3 cm and an inner diameter of 7 cm. The surface is covered with python skin. The stem is made of wood, with a total length of 77 cm. The headstock is flat-topped and inlaid with bone ornaments. Four axes and four strings. The bow is 72 cm long, and the bow tail is equipped with a screw, which can adjust the tension of the bow hair. Fully painted dark brown lacquer. This qin was originally collected by Mr. Mei Lanfang, a famous Peking Opera artist in my country. In 1958, Mr. Mei donated it to the country.