The Wera bit set Bit Check 30 BiTorsion 1 is a compact 30-piece bit set.It includes a bit holder Rapidaptor 1/4 "with quick-change chuck and 29 BiTorsion bits, hard and tough (BTZ), for universal use. The BiTorsion system ensures longer service life by through a targeted tempering process, the hardness of the shaft opposite the output peak to about 20 % is reduced. This torsion zone absorbs higher loads. When BiTorsion holder integrated torsion spring takes smaller loads. in the workplace can be the bit checks stand so that the tool is always ready to hand.