This is for four (4) quality marine grade stainless steel (AISI 316) M6 lifting eye nut. Each bolt is stamped 316 and M6 (for the size). The bolts are manufactured in the metric of M6. 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.