Insty-Bit Phillips high impact driver bits feature a precision tip design for ideal fitment of screw to bit, reducing breakage. These bits include "Impact-Zone®" geometry which is designed to flex and absorb a high degree of torque.  Incredibly high shock and torque resistance results from advanced metallurgy and heat treatment.  Designed to work great in impact drivers where you need a much higher rotational torque than traditional drills.  The 2" bits feature a power groove for quick change chucks.