MaterialThe drill is made of hardened steel to ensure this drill is ready f any hobby precision wk you can throw at it, to hle your precision builds. Various Sizes Comes with 1 mini pin vise 25 twist drill bits: 0.5/0.6mm (5 pieces f each size), 1.0mm (3 pieces), 1.2/1.5/1.8/2.0/2.35/3.0mm ( 2 pcs f each size). The pin vise drill kit of different sizes can meet your different needs. AdjustableIt can firmly hold thin drill bits. The tightening thread (female thread) must fit the underlying metal crectly be stable. This h drill has an adjustable drill bit holder which matches different sizes of drill bits you use. Wide ApplicationCompact size, useful f electronic assembly, tooling, model making , winding, home renovation. This ptable mini rotary drill is easy to operate with grooved hle design, you can hold it in your h easily comftably. Note: The data are all manual measurement, please allow some err of 1 - 3cm, due to the difference in light display, there will be a certain col difference, depending on the physical object received.