The drill bit is initially manually tightened in the jaws by turning the front ring of the chuck clockwise. Then, while drilling, the resistance applied on the drill bit leads the jaws in a tightening movement. The chuck therefore continues to tighten automatically while drilling. It is self-tightening.

This chuck is quite heavy, does not rotate from right to left, nor in hammer drill mode, unless it is equipped with an appropriate locking system.

It can be used on professional portable drills and on fixed column drills.

The drill bit is manually permanently tightened between the jaws by turning the front ring of the chuck in a clockwise manner.The chuck does not continue to tighten itself while drilling.

This chuck is light and operates in right-left rotations. It also functions in hammer-drill mode provided that it is equipped with a ratchet locking system.