This is for one (1) quality marine grade stainless steel (AISI 316) D Ring Welded 6mm x 50mm ID (1/4" x 2"). Each D Ring is stamped 316. 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. Black Nitride products undergo thermal chemical diffusion and quench bath treatments for unmatched durability and performance. With a case depth of 0.001", they offer increased wear resistance, improved fatigue strength, enhanced lubricity, and corrosion production. Black Nitride products are ideal for demanding applications while maintaining a sleek matte, professional look.