--Excellent workmanship 0.5-3.2mm drill. --Drill Collet size: 0.5/0.8/1.0/1.6/1.8/2.0/2.2/2.4/3.0/3.2mm. --Use with twisting-drills like a mini hand DRLL for drilling holes in board abs, planks, cardboard. --This 0.5-3.2mm Twisting-Drill Collet Set is made of copper with excellent workmanship. --Bui..