This listing is for (4) DIN315 5/16" wing nuts. These are threaded nuts with wings on opposite sides of the body. The wings can be used for manual tightening. No tools are needed for this product. These nuts are ideal for fastening two parts together. 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.