zvd 3 piece 412mm 420mm 432mm helical groove triangular shank step drill bit set triangular shank titanium step drill bit set convenient drill bits

this cobalt step drill bit set is a must have for home repairs and carpentry work, like drilling holes in plastic, aluminum and many other types of boards. if you are looking for this tool, give it a try features 3 piece set there are three drill bits with different specifications 4 12mm, 4 20mm and