Sea willow bracelets and sea willow in Phnom Penh-also known as black (horny) corals-inhabit hard seabed with water depth of 15-20m, or deeper coral rocks and rocks. Its branches are slender and beautiful, flexible in texture, and do not rot when exposed to water. Because its shape is similar to that of willow trees on land, it is named sea willow. Sea willow is easily misunderstood as a tree because of its name, but scientific research shows that sea willow is a marine animal, belonging to coelenterate and Corallinae. Corrosion resistance: willow is dense and hard, with the characteristics of "water seepage does not rot, fire does not damage" Therefore, it is also known as the "underwater Shenmu". 1958 an ancient tomb of the song dynasty was excavated near the site of the ancient Jinshi inspector in guanluwei village, Dongshan island. From the funerary objects, some intact funerary objects such as bracelets and kung fu tea sets carved by sea willows were found. According to historical records, Guanluxu Village was once the place where the last emperor of Song Dynasty, Zhao Bing and the left and right prime ministers Lu Xiufu and Chen fled, so it was called Guanluxu Village, with a history of more than 700 years. It can be seen how amazing the corrosion resistance of sea willow is.