The PNOZ X product range includes different versions of two-hand safety relays to meet various safety requirements. Specifically, the Type IIIC and Type IIIA versions are designed in accordance with the EN 574 standard, which defines the performance requirements for two-hand controls.
This is a higher safety category under the EN 574 standard, designed to offer a higher level of reliability and fault tolerance. http://www.pilz.com Type IIIC provides a high level of safety by ensuring that both pushbuttons must be pressed simultaneously and continuously. It often involves more sophisticated monitoring and redundancy features.