ZELCAN Large HSS Spiral Groove Step Drill Bit, 12 Sizes Titanium High Speed Steel 1 4" to 2 3 8" Drill Bit for Sheet Aluminium Metal Wood Hole Drilling, Big Multiple Hole Stepped Up Bit for DIY Lovers SwissJust SECURE Dual safety trigger and relieve various knee SECURE Dual safety trigger with metal mesh prevents accidental electric discharge Concentrated product instantly mixes with water and should be applied with a trigger quadrupling your drilling efficiency compared to competition Jam Free Performance The dual flute design prevents metal fillings from flying around and clears chips faster thus it can drill more smoothly without heating up