This is for four (4) quality marine grade stainless steel (AISI 316) quick link 3/8". Each quick link is stamped 316 and laser etched with size and and the makers mark. The quick links are marked in the US specification style of 3/8". The metric equivalent is generally considered to be 10mm. 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. Working Load Limit = 3960 lbs