This Ss shovan Drill Bit Set contain 3 size: 4-12mm, 4-20mm and 4-32 mm, Supplied with a portable fabric bag.Two-fluted design provides faster, smoother drilling, Provided with small pressure and the sets can cut through wood, plastic and other surfaces thickness under 5mm. Step Cone Drill Bits design for precision drilling different size holes from 4mm up to 32mm in diameter,optimum speed and accuracy.Titanium High Speed Steel Drill bits & Application: classic high speed steel with titanium coating for proven capability and durability in drilling holes in plastic, aluminum, copper and many other types of sheet metal.Titanium drill bit is particularly suitable for processing copper and aluminum pieces / mold steel / spring steel / cast iron pieces / iron and other metal materials.Quick Assemble: 1/4"(6.35mm) hex shank work with most drill or drills with 1/4" chuckall Products From Us Have Undergone Strict Quality Checks.if There Is Any Quality Problem Or You Are Not Satisfied With The Productcontact Us.we Will Give You The Best Solution.