Stainless Steel 316 Marine Grade Breaking Load 1930lbs Corrosion and rust resistant - for a long service life 1/2" UNC Thread Size - Pitch of 13 Easily attach cables or ropes This is for one (1) quality marine grade stainless steel (AISI 316) 1/2" UNC lifting eye bolt. Each bolt is stamped 316 and 1/2" and laser etched with the makers mark. The eye bolts are marked with 1/2" which refers to the thread size. The pitch of this thread is 13, which is the UNC standard. 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.