Milwaukee 4932479228 is a 3 piece Impact socket apaptor set. Each adaptor is made from proprietary steel and goes through a hear treat process for maximum strength and durability. Each adaptor has heavy duty construction for fastening capabilities in all impacts. Proprietary steel and heat treat process for maximum strength and durability. Heavy duty construction for fastening capabilities in all impacts. Contains; 1 x 1/4" Hex - 1/4" Square 1 x 1/4" Hex - 3/8" Square 1 x 1/4" Hex - 1/2" Square