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. Nw use with Milwaukee SHOCKWAVE Impact Duty insert magnetic nut drivers (1/4 in., 5/16 in., 3/8 in., 7/16 in., 1/2 in.).