This 16 pieces mixed drill bit set is suitable for metal, masonry and wood. Our high-quality drill bit set comprises HSS size 2, 3, 4, 5, 6 and 8mm, masonry size 4, 5, 6, 8 and 10mm, wood size 4, 5, 6, 8 and 10mm. These HSS drill bits are ideal, both for professional use and for DIY enthusiasts. Secure the workpiece to prevent movement when drilling. Reduce drill speed for larger diameter drill bits. Begin drilling slowly and never use sideways or apply undue pressure. Lubrication is recommended when drilling metals. Do not allow the flutes to clog during drilling.