Please read the profile before purchasing. Important requests regarding transactions are stated. Your understanding and agreement with all of them are key to a smooth transaction, so we appreciate your cooperation. Although the official name is unknown, this is a set of double-ended bolt snap hook clips (4 pieces, new). The material is molybdenum-added "316 stainless steel," a high-grade material that is particularly resistant to rust and durable among stainless steels. I myself have been using the same product in the ocean for many years, and I have never had any rust issues with simple rinsing maintenance. I have bulk stock purchased from the manufacturer, and I am selling them at a lower price than retail to clear out some equipment.