How jaws work?
The jaws fits in the jaw – holder while the rear booster spring pushes them forward and holds them in place.
By screwing the external sleeve the jaws are pushed backward by the nozzle (the depth of the nozzle determines the opening of the jaws: the longer the nozzle, the larger the diameter of the nail you can pull); they open up and are ready to receive the blind rivet.
By trigging the riveter the group is pulled back, the spring pushes the jaws so the blind rivet is grabbed.
Continuing the stroke, the jaws pull the nail untill it breaks, ensuring the deformation on the rivet.