What specifications of ritual chains will be used in the ring chain? There are usually more specifications of 6mm, 6.3mm, 7.1mm, 8mm, and 10mm. The internal length is generally three times the diameter. The material of the chain is 20mn2, commonly known as manganese steel. The chain shows that the treatment can be polished, black, and carburizing for primary colors. The black chain can slow the chain oxidation and rust, and the appearance is more beautiful. The surface of the chain of carburizing is higher and the price is more expensive. Usually high -speed gourds will use this chain.