Made of S2 steel and heat treated, high strenth, wear and shock resistant. Magnetic collar design can hold the cross headed tightly, reduce the slippage, durable for long life. PH2 cross head screwdriver bits designed for drywall screws, limit screw penetration and damage to board. Ideal screwdriver bit set for household appliances, precision instruments industry, furniture industry power tools 1/4-Inch hex shank screwdriver bits fit for electric screwdriver, electric power drills, hand screwdrivers and impact drivers