A safety relay is a type of electrical relay that is designed to disconnect power to a machine or system when it detects an unsafe condition. Safety relays are commonly used in industrial automation applications to provide an additional level of protection for workers and equipment.

An output extension is a device that expands the number of output connections available on a control module or PLC. An output extension module typically attaches to the existing module or PLC and provides additional output channels, allowing the control system to control more devices.

Spring-loaded terminals are a type of connector used in electrical systems. They are designed to hold wires in place using a spring mechanism, making it easy to connect and disconnect wires without the need for tools. Spring-loaded terminals are commonly used in industrial and commercial applications where quick and easy wiring is important. They are often used in conjunction with control modules and safety relays, making them an important component of many automated systems.