Union Smoke smoke safety systems are manufactured in Italy as a brand of UR Fog. They differ from the fog systems by the sight obstruction technology. While fog is produced by spraying the liquid into a heat exchanger, the smoke systems are pyrotechnic devices that produce smoke from solid substances without heating.

Once activated, the system cannot be interrupted, as the entire cartridge is consumed in one shot. Unlike the fog system, the smoke safety system is characterized by a persistent odor and leaves a light dust residue.