Aslo referred to as Belleville Washers, Disc Springs, Spring Washers, Conical Washers, Cupped Spring Washers, or Conical Spring Washers Used to apply a flexible pre-load to a bolted joint or bearing - Can be used in a stack below the bolt head to apply a greater pre-load Corrosion resistant 18-8 stainless steel Variety of uses including vibration reduction and pressure indicators Commonly used in automotive applications, aerospace, vehicles and general machinery