Wera 05048680001 797 B/4/1 BiTorsion Quick-Release Bit Holders are suitable for 1/4'' DIN 3126-C 6,3 und E 6,3 (ISO 1173) hexagon insert bits and Wera Series 1 and 4, feature a BiTorsion design for long service life, with strong permanent magnet. Wera BiTorsion bit holders feature a torsion zone that diverts the kinetic energy away from the drive tip during such peak loads.