This is for two (2) quality marine grade stainless steel (AISI 316) 1/2" UNC heavy duty lifting eye nut. Each nut is stamped 316 and 1/2" (for the size). The nuts are manufactured in the US style of 1/2" UNC - pitch of 13. 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.