The Expander SW4 is an extension for magnetic and RC switches and is designed for switching multiple devices simultaneously. The JETI model company produces a wide range of devices that can be switched by magnetic switch or RC switch. The Expander SW4 allows you to combine the switching duties so that several devices can be controlled using one only element. Furthermore, some outputs are optically isolated to prevent interference. This makes it is possible to isolate control of devices which may be sensitive to electric interference.