Milwaukee® SHOCKWAVE Impact Duty™ Magnetic Bit Tip Holders are engineered for extreme durability and up to 10x life. Made from proprietary steel and heat treated to control hardness, the SHOCKWAVE Impact Duty™ magnetic bit holders feature a powerful magnet allowing for a secure grip and unyielding bit engagement. The 2-piece construction of the holders is the optimal assembly for abusive applications. Now use with Milwaukee® SHOCKWAVE Impact Duty™ Insert Magnetic Nut Drivers (1/4", 5/16", 3/8", 7/16", 1/2").