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 10 the metric size and 316 the grade. This is an M10 metric turnbuckle. The imperial equivalent is generally considered to be 3/8". 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.