These sets contain multiple straight-flute drill bits in different sizes. They ensure users have a range of bits on hand for maintenance and repair tasks. Straight-flute drill bits are stronger than spiral-flute drill bits and resist breaking when drilling into hard and abrasive materials, such as hardened steels with a Rockwell hardness of 35 to 60 HRC. The bits provide free-cutting action, generate minimal heat during drilling, and leave a smooth finish on the hole without requiring a reaming pass. The bits' straight flutes help with chip evacuation in horizontal drilling applications.