SHOCKWAVE impactduty magnetic bit holders are engineered for extreme durability and up to 10X life Made from proprietary steel and heattreated to control hardness, the shockwave impact duty magnetic bit holders feature a powerful magnet allowing for a secure grip and unyielding bit engagement The twopiece construction of the holders is the optimal assembly for abusive applications Now use with Milwaukee Shockwave Impact Duty Insert Magnetic Nut Drivers