CAD pullers and thrusters/actuators are basically the same, except that they work in reverse. The motion of the puller is inward while the thruster is outward. Power derived from a pressure cartridge moves a piston in the desired direction.

Pullers are used primarily for releasing components previously attached (i.e. retaining rings, pins, etc.) while thrusters, working in reverse, are moving masses or mechanisms.

Puncture devices are thrusters specifically designed for opening pressure vessels.

Data Sheet: Thrusters, Actuators and Pin Pullers