Wera TH Torsion Zone Bits.-Wera Torsion technology increases service life of the bit.-Torsion-style design reduces premature wear, extra hard. -Made from high grade steel and precision manufactured.-TH bits are specifically designed for use in high torque screwdriving applications, such as wood. -Combined with the BiTorsion Rapidaptor bit holder, performance is further improved. -Ideal for use in general construction. -Use the Wera BiTorsion Bit Holder to increase the service life of the bit.