Proprietary steel and heat treat process for maximum strength and durability. Heavy duty construction for fastening capabilities in all impacts. Diameter 1/4" Milwaukee Shockwave Impact Duty Socket Adapters are engineered for extreme durability and up to 10x life. Made from proprietary steel and heat treated to control hardness, the Shockwave Impact Duty Socket Adapters provide fastening capabilities with all impacts. Broadly targeting cordless users, the Shockwave Impact Duty accessory line is not only ideal for heavy duty impact applications, but delivers a full system solution for all the user's drilling and fastening needs.