Milwaukee SHOCKWAVE? Impact Duty? insert magnetic nut drivers 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 nut drivers feature a powerful magnet allowing for a secure grip and unyielding bit engagement. The bits feature color-coded rings for quick and easy size identification and a chamfered edge to allow for fastening in tight spaces. Designed for use with Milwaukee SHOCKWAVE? magnetic bit tip holders 2.36 in, 3 in, 6 in, 12 in, 30 deg Knuckle? pivoting bit holder and all bit tip holders.