The MILWAUKEE SHOCKWAVE 3-1/2 Square 1 Impact Duty Bit 2 Pack is engineered to be the most durable, best fitting driver bits on the market. The square bits feature Wear Guard Tip for increased wear resistance, which protects the fit over the life of the bit. The impact driver bits have an optimized Shockzone for each tip type and length of driver bit to absorb peak torque and prevent breaking. The Custom Alloy76 Steel is customized and heat treated per tip type to extend the life of the driver but by up to 50X vs. competitive impact driver bits. The MILWAUKEE SHOCKWAVE Impact Duty driver bits are built to deliver extreme durability for the most demanding applications.