The PNOZ X series from Pilz is indeed a range of safety relays commonly used for monitoring safety gates, emergency stop buttons (E-STOP), light barriers, light curtains, and limit switches. These safety relays are designed to ensure the safe functioning of machinery and equipment by monitoring safety-related inputs and initiating a safe shutdown or control response if any unsafe conditions are detected. http://www.pilz.com
If you are looking to purchase safety relays, I recommend contacting authorized distributors or suppliers of Pilz products. You can find these products through industrial automation suppliers, electrical component distributors, or directly through Pilz’s official channels. http://www.pilz.com