The Pilz PZE X4 is a contact expansion module designed to increase the number of available safety contacts in a safety circuit. It is used in conjunction with a base safety relay unit, such as those from the PNOZ X, PNOZsigma, or PNOZelog series. This module provides four additional normally open (N.O.) safety-rated contacts, allowing for the connection of more actuators or for creating multiple redundant switching paths. Its compact design and reliable performance make it an essential component for expanding safety functions in applications like emergency stop circuits, safety gates, and light curtain monitoring, ensuring compliance with international safety standards.