60PC Drill & Drive Set is engineered to be the Most Durable, Best Fitting driver bits on the market. The TIP delivers increased wear resistance which protects the impact bit's fit over the life of the bit. The is optimized for each tip type and length of driver bit in the set to absorb peak torque and prevent breaking. The driver bits are made from CUSTOM ALLOY steel and a proprietary heat treatment process to extend bit life, providing up to 50X life versus other impact driver bits on the market.