This is for one (1) high quality Marine Grade Stainless Steel (AISI 316) 1/2" UNC Helicopter. Each bolt is stamped with 124 and 1/2 inch and laser engraved with the marking. The eye bolts are marked with 1/2" which refers to thread size. Do not use for overhead lifting. AISI 316 stainless steel is a premium stainless steel and is considered by many to be the best in class. 316 stainless steel is corrosion resistant and very durable even under the toughest conditions.