This is for ten (10) quality marine grade stainless steel (AISI 316) quick links 4mm. The Imperial equivalent is generally considered to be 5/32". Each quick link is stamped 316. 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 for a long service life. Working Load Limit 616lbs.