This is a quality marine grade stainless steel (AISI 316) chain specifically cut for anchor chain. The link size is 8mm or 5/16" equivalent. Included are two oversized marine grade stainless steel (AISI 316) anchor shackles. Both the link and the shackles are marked in the European specification style of 8mm (for the chain link size) and 10mm (for the shackle size). The Imperial equivalent is generally considered to be 5/16" for the chain link size. AISI 316 stainless is a premium grade of stainless and is considered by many to be best in class. 316 stainless is corrosion resistant and very durable even in the harshest of conditions.