Chain block has different chain rows according to different tonnage. The tonnage of chain block is relatively large, ranging from 1 ton to 50 tons. Commonly used specifications are 1 ton, 2 tons, 3 tons, 5 tons and 10 tons. Single-row chain is used for lifting one ton, and double-chain is used for lifting three tons and five tons. 10 tons adopts four-row chain. The standard chain length is 3 meters, and the required chain length can be customized according to the use requirements. Chain block is suitable for use in environments where there is no power supply or the power supply is inconvenient. The types and appearances of chain block can be divided into circular chain block and triangular chain block.