This is for one (1) quality marine grade stainless steel (AISI 316) anchor swivel connector. Each swivel is stamped 316 and with the max load rating of 5500lbs. The swivels are marked in the imperial specification style of 5/16". The metric equivalent is generally considered to be 8mm. Not to be used for overhead lifting. 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.