HSS Titanium Coated Step Drill Bits Set，Shank 1/4&quot; &amp; 3/8&quot;<br /><br />Features:<br />1. Unique ladder structure， 1/4”&amp; 3/8&quot; round shank. Straight grooves.<br />2. Automatically Deburrs Holes. Two-flute Design Gives You Faster， Smooth