This is a quality marine grade stainless steel (AISI 316) chain specifically cut for anchor chain. The link size is 1/4" or 6mm equivalent. The chain includes oversized chain links on both ends for easy attachment. Included are two oversized marine grade stainless steel (AISI 316) anchor shackles. Each US style shackle is 5/16" (8mm) with an oversized pin of 3/8". The total length of chain is 4' measured before the shackles are added. The chain link is in the US specification style of 1/4" (for the chain link size) and the shackles are made in the imperial style of 5/16". The metric equivalent is generally considered to be 6mm for the chain link size and 8mm for the shackles. This is a medium duty chain, good for marine environments and is ideal for a small boat or other light applications. 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.