4 x 90 head geometry prevents locking when hitting rebar on the side. Bit is designed for longer life when drilling in concrete. As an additional benefit, it can crush through and pulverize rebar when drilling in reinforced concrete applications. 4 fluted reinforced flute geometry uniformly distributes the dust through the flute for even flute wear. The reinforced geometry reduces vibrations and transfer more energy from the powertool motor to the tip of the drill bit.