This is for one (1) quality marine grade stainless steel (AISI 316) turnbuckle (or open body) eye and eye with locknuts. Each turnbuckle is stamped both 5 the metric size and 316 the grade. This is an M5 metric turnbuckle. The imperial equivalent is generally considered to be 3/16". 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.