Sonoff SV Safe Voltage Low Voltage WiFi Wireless Switch. Relay Module DC 5V-24V Smart Home Remote Control The low voltage light switch supports 5-24V power supply. Sonoff SV Low Voltage WiFi Switch is a cost-effective device that offers customers smart home control. The Low Voltage WiFi Switch is a WiFi based wireless switch that can connect to a wide range of devices. The Sonoff SV low voltage remote switch transmits data to a cloud platform via the WiFi router, which allows customers to remotely control all connected appliances, via the eWeLink mobile application.