This is for ten (10) quality marine grade stainless steel (AISI 316) thimbles. Each thimble is stamped 316. For rope size of 1/8" or 3mm. 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.