This is a quality marine grade stainless steel (AISI 316) 1/4" (7mm) NACM chain specifically cut for anchor chain. The link size is 7mm or 1/4" equivalent. Included are two oversized marine grade stainless steel (AISI 316) anchor shackles. Each shackle is 8mm (5/16"). The total length of chain is 4' measured before the shackles are added. The chain link size is the European specification style of 7mm and the shackle is 8mm (5/16") (for the shackle 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.