This is for two (2) quality marine grade stainless steel (AISI 316) bow shackles. Each shackle is stamped 316 and laser etched 5/16" with the manufacturer's mark. The shackles are marked in the US specification style of 5/16" (for the shackle size). The Metric equivalent is generally considered to be 8mm. This is a forged shackle, which for load bearing applications is better than a cast shackle. 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. Breaking Load = 5500lbs