HST chain block is characterized by compact structure, light weight, durability, high mechanical efficiency and small hand pull. Small space between two hooks, especially suitable for narrow working space, safe and reliable, easy maintenance. The cover and gear has good rigidity, high strength, good anti-collision ability, and can effectively protect the internal components of the body and other advantages, which is closely related to his design material alloy steel, production process high-temperature forging, and design technology double ratchet braking.