Sirius Safety Relay Basic Unit Standard Series electronic release circuits 2 release circuits plus 1 monitoring circuit Us = 24 V DC screw connection safety relay Sirius 3SK1 for stand-alone safety applications. The Basic Units Standard 3SK111 are characterized by simple and variable functionality, providing an economical entry into the world of safety relays. They are ideally suited for safety functions with only a few sensors and a limited number of release circuits. These devices have comprehensive global approvals, making them well-suited for international use and export. The devices are available in a 24 V version or with a wide voltage range, relay or semiconductor outputs, and consistently with screw or spring clamp connections (Push-In). Extensive accessories such as sealing covers, mounting brackets for wall installation, and coding pins facilitate handling. The safety relays 3SK replace the proven series 3TK28. Safety is a Sirius business.